[u/mdw/putty] / terminal.c

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#include <time.h>
#include <assert.h>
#include "putty.h"
#include "tree234.h"

#define VT52_PLUS

#define CL_ANSIMIN      0x0001         /* Codes in all ANSI like terminals. */
#define CL_VT100        0x0002         /* VT100 */
#define CL_VT100AVO     0x0004         /* VT100 +AVO; 132x24 (not 132x14) & attrs */
#define CL_VT102        0x0008         /* VT102 */
#define CL_VT220        0x0010         /* VT220 */
#define CL_VT320        0x0020         /* VT320 */
#define CL_VT420        0x0040         /* VT420 */
#define CL_VT510        0x0080         /* VT510, NB VT510 includes ANSI */
#define CL_VT340TEXT    0x0100         /* VT340 extensions that appear in the VT420 */
#define CL_SCOANSI      0x1000         /* SCOANSI not in ANSIMIN. */
#define CL_ANSI         0x2000         /* ANSI ECMA-48 not in the VT100..VT420 */
#define CL_OTHER        0x4000         /* Others, Xterm, linux, putty, dunno, etc */

#define TM_VT100        (CL_ANSIMIN|CL_VT100)
#define TM_VT100AVO     (TM_VT100|CL_VT100AVO)
#define TM_VT102        (TM_VT100AVO|CL_VT102)
#define TM_VT220        (TM_VT102|CL_VT220)
#define TM_VTXXX        (TM_VT220|CL_VT340TEXT|CL_VT510|CL_VT420|CL_VT320)
#define TM_SCOANSI      (CL_ANSIMIN|CL_SCOANSI)

#define TM_PUTTY        (0xFFFF)

#define compatibility(x) \
    if ( ((CL_##x)&compatibility_level) == 0 ) {        \
       termstate=TOPLEVEL;                              \
       break;                                           \
    }
#define compatibility2(x,y) \
    if ( ((CL_##x|CL_##y)&compatibility_level) == 0 ) { \
       termstate=TOPLEVEL;                              \
       break;                                           \
    }

#define has_compat(x) ( ((CL_##x)&compatibility_level) != 0 )

static int compatibility_level = TM_PUTTY;

static tree234 *scrollback;            /* lines scrolled off top of screen */
static tree234 *screen;                /* lines on primary screen */
static tree234 *alt_screen;            /* lines on alternate screen */
static int disptop;                    /* distance scrolled back (0 or -ve) */

static unsigned long *cpos;            /* cursor position (convenience) */

static unsigned long *disptext;        /* buffer of text on real screen */
static unsigned long *dispcurs;        /* location of cursor on real screen */
static unsigned long curstype;         /* type of cursor on real screen */

#define VBELL_TIMEOUT (TICKSPERSEC/10) /* visual bell lasts 1/10 sec */

struct beeptime {
    struct beeptime *next;
    unsigned long ticks;
};
static struct beeptime *beephead, *beeptail;
int nbeeps;
int beep_overloaded;
long lastbeep;

#define TSIZE (sizeof(unsigned long))
#define fix_cpos do { cpos = lineptr(curs.y) + curs.x; } while(0)

static unsigned long curr_attr, save_attr;
static unsigned long erase_char = ERASE_CHAR;

typedef struct {
    int y, x;
} pos;
#define poslt(p1,p2) ( (p1).y < (p2).y || ( (p1).y == (p2).y && (p1).x < (p2).x ) )
#define posle(p1,p2) ( (p1).y < (p2).y || ( (p1).y == (p2).y && (p1).x <= (p2).x ) )
#define poseq(p1,p2) ( (p1).y == (p2).y && (p1).x == (p2).x )
#define posdiff(p1,p2) ( ((p1).y - (p2).y) * (cols+1) + (p1).x - (p2).x )
#define incpos(p) ( (p).x == cols ? ((p).x = 0, (p).y++, 1) : ((p).x++, 0) )
#define decpos(p) ( (p).x == 0 ? ((p).x = cols, (p).y--, 1) : ((p).x--, 0) )

/* Product-order comparisons for rectangular block selection. */
#define posPlt(p1,p2) ( (p1).y <= (p2).y && (p1).x < (p2).x )
#define posPle(p1,p2) ( (p1).y <= (p2).y && (p1).x <= (p2).x )

static bufchain inbuf;                 /* terminal input buffer */
static pos curs;                       /* cursor */
static pos savecurs;                   /* saved cursor position */
static int marg_t, marg_b;             /* scroll margins */
static int dec_om;                     /* DEC origin mode flag */
static int wrap, wrapnext;             /* wrap flags */
static int insert;                     /* insert-mode flag */
static int cset;                       /* 0 or 1: which char set */
static int save_cset, save_csattr;     /* saved with cursor position */
static int save_utf, save_wnext;       /* saved with cursor position */
static int rvideo;                     /* global reverse video flag */
static unsigned long rvbell_startpoint;/* for ESC[?5hESC[?5l vbell */
static int cursor_on;                  /* cursor enabled flag */
static int reset_132;                  /* Flag ESC c resets to 80 cols */
static int use_bce;                    /* Use Background coloured erase */
static int blinker;                    /* When blinking is the cursor on ? */
static int tblinker;                   /* When the blinking text is on */
static int blink_is_real;              /* Actually blink blinking text */
static int term_echoing;               /* Does terminal want local echo? */
static int term_editing;               /* Does terminal want local edit? */
static int sco_acs, save_sco_acs;      /* CSI 10,11,12m -> OEM charset */
static int vt52_bold;                  /* Force bold on non-bold colours */
static int utf_state;                  /* Is there a pending UTF-8 character */
static int utf_char;                   /* and what is it so far. */
static int utf_size;                   /* The size of the UTF character. */
static int printing, only_printing;    /* Are we doing ANSI printing? */
static int print_state;                /* state of print-end-sequence scan */
static bufchain printer_buf;           /* buffered data for printer */
static printer_job *print_job;

static int xterm_mouse;                /* send mouse messages to app */

static unsigned long cset_attr[2];

/*
 * Saved settings on the alternate screen.
 */
static int alt_x, alt_y, alt_om, alt_wrap, alt_wnext, alt_ins, alt_cset, alt_sco_acs, alt_utf;
static int alt_t, alt_b;
static int alt_which;

#define ARGS_MAX 32                    /* max # of esc sequence arguments */
#define ARG_DEFAULT 0                  /* if an arg isn't specified */
#define def(a,d) ( (a) == ARG_DEFAULT ? (d) : (a) )
static int esc_args[ARGS_MAX];
static int esc_nargs;
static int esc_query;
#define ANSI(x,y)       ((x)+((y)<<8))
#define ANSI_QUE(x)     ANSI(x,TRUE)

#define OSC_STR_MAX 2048
static int osc_strlen;
static char osc_string[OSC_STR_MAX + 1];
static int osc_w;

static char id_string[1024] = "\033[?6c";

static unsigned char *tabs;

static enum {
    TOPLEVEL,
    SEEN_ESC,
    SEEN_CSI,
    SEEN_OSC,
    SEEN_OSC_W,

    DO_CTRLS,

    SEEN_OSC_P,
    OSC_STRING, OSC_MAYBE_ST,
    VT52_ESC,
    VT52_Y1,
    VT52_Y2,
    VT52_FG,
    VT52_BG
} termstate;

static enum {
    NO_SELECTION, ABOUT_TO, DRAGGING, SELECTED
} selstate;
static enum {
    LEXICOGRAPHIC, RECTANGULAR
} seltype;
static enum {
    SM_CHAR, SM_WORD, SM_LINE
} selmode;
static pos selstart, selend, selanchor;

static short wordness[256] = {
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,            /* 01 */
    0, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    2, 2, 1, 1, 1, 1, 1, 1,            /* 23 */
    1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    2, 2, 2, 1, 1, 1, 1, 2,            /* 45 */
    1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    2, 2, 2, 1, 1, 1, 1, 1,            /* 67 */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1,            /* 89 */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1,            /* AB */
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1,
    2, 2, 2, 2, 2, 2, 2, 2,            /* CD */
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1,
    2, 2, 2, 2, 2, 2, 2, 2,            /* EF */
};

#define sel_nl_sz  (sizeof(sel_nl)/sizeof(wchar_t))
static wchar_t sel_nl[] = SEL_NL;
static wchar_t *paste_buffer = 0;
static int paste_len, paste_pos, paste_hold;

/*
 * Internal prototypes.
 */
static void do_paint(Context, int);
static void erase_lots(int, int, int);
static void swap_screen(int, int, int);
static void update_sbar(void);
static void deselect(void);
static void term_print_finish(void);

/*
 * Resize a line to make it `cols' columns wide.
 */
unsigned long *resizeline(unsigned long *line, int cols)
{
    int i, oldlen;
    unsigned long lineattrs;

    if (line[0] != (unsigned long)cols) {
        /*
         * This line is the wrong length, which probably means it
         * hasn't been accessed since a resize. Resize it now.
         */
        oldlen = line[0];
        lineattrs = line[oldlen + 1];
        line = srealloc(line, TSIZE * (2 + cols));
        line[0] = cols;
        for (i = oldlen; i < cols; i++)
            line[i + 1] = ERASE_CHAR;
        line[cols + 1] = lineattrs & LATTR_MODE;
    }

    return line;
}

/*
 * Retrieve a line of the screen or of the scrollback, according to
 * whether the y coordinate is non-negative or negative
 * (respectively).
 */
unsigned long *lineptr(int y, int lineno)
{
    unsigned long *line, *newline;
    tree234 *whichtree;
    int treeindex;

    if (y >= 0) {
        whichtree = screen;
        treeindex = y;
    } else {
        whichtree = scrollback;
        treeindex = y + count234(scrollback);
    }
    line = index234(whichtree, treeindex);

    /* We assume that we don't screw up and retrieve something out of range. */
    assert(line != NULL);

    newline = resizeline(line, cols);
    if (newline != line) {
        delpos234(whichtree, treeindex);
        addpos234(whichtree, newline, treeindex);
        line = newline;
    }

    return line + 1;
}

#define lineptr(x) lineptr(x,__LINE__)
/*
 * Set up power-on settings for the terminal.
 */
static void power_on(void)
{
    curs.x = curs.y = alt_x = alt_y = savecurs.x = savecurs.y = 0;
    alt_t = marg_t = 0;
    if (rows != -1)
        alt_b = marg_b = rows - 1;
    else
        alt_b = marg_b = 0;
    if (cols != -1) {
        int i;
        for (i = 0; i < cols; i++)
            tabs[i] = (i % 8 == 0 ? TRUE : FALSE);
    }
    alt_om = dec_om = cfg.dec_om;
    alt_wnext = wrapnext = alt_ins = insert = FALSE;
    alt_wrap = wrap = cfg.wrap_mode;
    alt_cset = cset = 0;
    alt_utf = utf = 0;
    alt_sco_acs = sco_acs = 0;
    cset_attr[0] = cset_attr[1] = ATTR_ASCII;
    rvideo = 0;
    in_vbell = FALSE;
    cursor_on = 1;
    big_cursor = 0;
    save_attr = curr_attr = ATTR_DEFAULT;
    term_editing = term_echoing = FALSE;
    ldisc_send(NULL, 0, 0);            /* cause ldisc to notice changes */
    app_cursor_keys = cfg.app_cursor;
    app_keypad_keys = cfg.app_keypad;
    use_bce = cfg.bce;
    blink_is_real = cfg.blinktext;
    erase_char = ERASE_CHAR;
    alt_which = 0;
    term_print_finish();
    {
        int i;
        for (i = 0; i < 256; i++)
            wordness[i] = cfg.wordness[i];
    }
    if (screen) {
        swap_screen(1, FALSE, FALSE);
        erase_lots(FALSE, TRUE, TRUE);
        swap_screen(0, FALSE, FALSE);
        erase_lots(FALSE, TRUE, TRUE);
    }
}

/*
 * Force a screen update.
 */
void term_update(void)
{
    Context ctx;
    ctx = get_ctx();
    if (ctx) {
        int need_sbar_update = seen_disp_event;
        if (seen_disp_event && cfg.scroll_on_disp) {
            disptop = 0;               /* return to main screen */
            seen_disp_event = 0;
            need_sbar_update = TRUE;
        }
        if (need_sbar_update)
            update_sbar();
        do_paint(ctx, TRUE);
        sys_cursor(curs.x, curs.y - disptop);
        free_ctx(ctx);
    }
}

/*
 * Called from front end when a keypress occurs, to trigger
 * anything magical that needs to happen in that situation.
 */
void term_seen_key_event(void)
{
    /*
     * On any keypress, clear the bell overload mechanism
     * completely, on the grounds that large numbers of
     * beeps coming from deliberate key action are likely
     * to be intended (e.g. beeps from filename completion
     * blocking repeatedly).
     */
    beep_overloaded = FALSE;
    while (beephead) {
        struct beeptime *tmp = beephead;
        beephead = tmp->next;
        sfree(tmp);
    }
    beeptail = NULL;
    nbeeps = 0;

    /*
     * Reset the scrollback on keypress, if we're doing that.
     */
    if (cfg.scroll_on_key) {
        disptop = 0;                   /* return to main screen */
        seen_disp_event = 1;
    }
}

/*
 * Same as power_on(), but an external function.
 */
void term_pwron(void)
{
    power_on();
    fix_cpos;
    disptop = 0;
    deselect();
    term_update();
}

/*
 * When the user reconfigures us, we need to check the forbidden-
 * alternate-screen config option, disable raw mouse mode if the
 * user has disabled mouse reporting, and abandon a print job if
 * the user has disabled printing.
 */
void term_reconfig(void)
{
    if (cfg.no_alt_screen)
        swap_screen(0, FALSE, FALSE);
    if (cfg.no_mouse_rep) {
        xterm_mouse = 0;
        set_raw_mouse_mode(0);
    }
    if (cfg.no_remote_charset) {
        cset_attr[0] = cset_attr[1] = ATTR_ASCII;
        sco_acs = alt_sco_acs = 0;
        utf = 0;
    }
    if (!*cfg.printer) {
        term_print_finish();
    }
}

/*
 * Clear the scrollback.
 */
void term_clrsb(void)
{
    unsigned long *line;
    disptop = 0;
    while ((line = delpos234(scrollback, 0)) != NULL) {
        sfree(line);
    }
    update_sbar();
}

/*
 * Initialise the terminal.
 */
void term_init(void)
{
    screen = alt_screen = scrollback = NULL;
    disptop = 0;
    disptext = dispcurs = NULL;
    tabs = NULL;
    deselect();
    rows = cols = -1;
    power_on();
    beephead = beeptail = NULL;
    nbeeps = 0;
    lastbeep = FALSE;
    beep_overloaded = FALSE;
}

/*
 * Set up the terminal for a given size.
 */
void term_size(int newrows, int newcols, int newsavelines)
{
    tree234 *newalt;
    unsigned long *newdisp, *line;
    int i, j;
    int sblen;
    int save_alt_which = alt_which;

    if (newrows == rows && newcols == cols && newsavelines == savelines)
        return;                        /* nothing to do */

    deselect();
    swap_screen(0, FALSE, FALSE);

    alt_t = marg_t = 0;
    alt_b = marg_b = newrows - 1;

    if (rows == -1) {
        scrollback = newtree234(NULL);
        screen = newtree234(NULL);
        rows = 0;
    }

    /*
     * Resize the screen and scrollback. We only need to shift
     * lines around within our data structures, because lineptr()
     * will take care of resizing each individual line if
     * necessary. So:
     * 
     *  - If the new screen and the old screen differ in length, we
     *    must shunt some lines in from the scrollback or out to
     *    the scrollback.
     * 
     *  - If doing that fails to provide us with enough material to
     *    fill the new screen (i.e. the number of rows needed in
     *    the new screen exceeds the total number in the previous
     *    screen+scrollback), we must invent some blank lines to
     *    cover the gap.
     * 
     *  - Then, if the new scrollback length is less than the
     *    amount of scrollback we actually have, we must throw some
     *    away.
     */
    sblen = count234(scrollback);
    /* Do this loop to expand the screen if newrows > rows */
    for (i = rows; i < newrows; i++) {
        if (sblen > 0) {
            line = delpos234(scrollback, --sblen);
        } else {
            line = smalloc(TSIZE * (newcols + 2));
            line[0] = newcols;
            for (j = 0; j <= newcols; j++)
                line[j + 1] = ERASE_CHAR;
        }
        addpos234(screen, line, 0);
    }
    /* Do this loop to shrink the screen if newrows < rows */
    for (i = newrows; i < rows; i++) {
        line = delpos234(screen, 0);
        addpos234(scrollback, line, sblen++);
    }
    assert(count234(screen) == newrows);
    while (sblen > newsavelines) {
        line = delpos234(scrollback, 0);
        sfree(line);
        sblen--;
    }
    assert(count234(scrollback) <= newsavelines);
    disptop = 0;

    newdisp = smalloc(newrows * (newcols + 1) * TSIZE);
    for (i = 0; i < newrows * (newcols + 1); i++)
        newdisp[i] = ATTR_INVALID;
    sfree(disptext);
    disptext = newdisp;
    dispcurs = NULL;

    newalt = newtree234(NULL);
    for (i = 0; i < newrows; i++) {
        line = smalloc(TSIZE * (newcols + 2));
        line[0] = newcols;
        for (j = 0; j <= newcols; j++)
            line[j + 1] = erase_char;
        addpos234(newalt, line, i);
    }
    if (alt_screen) {
        while (NULL != (line = delpos234(alt_screen, 0)))
            sfree(line);
        freetree234(alt_screen);
    }
    alt_screen = newalt;

    tabs = srealloc(tabs, newcols * sizeof(*tabs));
    {
        int i;
        for (i = (cols > 0 ? cols : 0); i < newcols; i++)
            tabs[i] = (i % 8 == 0 ? TRUE : FALSE);
    }

    if (rows > 0)
        curs.y += newrows - rows;
    if (curs.y < 0)
        curs.y = 0;
    if (curs.y >= newrows)
        curs.y = newrows - 1;
    if (curs.x >= newcols)
        curs.x = newcols - 1;
    alt_x = alt_y = 0;
    wrapnext = alt_wnext = FALSE;

    rows = newrows;
    cols = newcols;
    savelines = newsavelines;
    fix_cpos;

    swap_screen(save_alt_which, FALSE, FALSE);

    update_sbar();
    term_update();
    back->size();
}

/*
 * Swap screens. If `reset' is TRUE and we have been asked to
 * switch to the alternate screen, we must bring most of its
 * configuration from the main screen and erase the contents of the
 * alternate screen completely. (This is even true if we're already
 * on it! Blame xterm.)
 */
static void swap_screen(int which, int reset, int keep_cur_pos)
{
    int t;
    tree234 *ttr;

    if (!which)
        reset = FALSE;                 /* do no weird resetting if which==0 */

    if (which != alt_which) {
        alt_which = which;

        ttr = alt_screen;
        alt_screen = screen;
        screen = ttr;
        t = curs.x;
        if (!reset && !keep_cur_pos)
            curs.x = alt_x;
        alt_x = t;
        t = curs.y;
        if (!reset && !keep_cur_pos)
            curs.y = alt_y;
        alt_y = t;
        t = marg_t;
        if (!reset) marg_t = alt_t;
        alt_t = t;
        t = marg_b;
        if (!reset) marg_b = alt_b;
        alt_b = t;
        t = dec_om;
        if (!reset) dec_om = alt_om;
        alt_om = t;
        t = wrap;
        if (!reset) wrap = alt_wrap;
        alt_wrap = t;
        t = wrapnext;
        if (!reset) wrapnext = alt_wnext;
        alt_wnext = t;
        t = insert;
        if (!reset) insert = alt_ins;
        alt_ins = t;
        t = cset;
        if (!reset) cset = alt_cset;
        alt_cset = t;
        t = utf;
        if (!reset) utf = alt_utf;
        alt_utf = t;
        t = sco_acs;
        if (!reset) sco_acs = alt_sco_acs;
        alt_sco_acs = t;
    }

    if (reset && screen) {
        /*
         * Yes, this _is_ supposed to honour background-colour-erase.
         */
        erase_lots(FALSE, TRUE, TRUE);
    }

    /*
     * This might not be possible if we're called during
     * initialisation.
     */
    if (screen)
        fix_cpos;
}

/*
 * Update the scroll bar.
 */
static void update_sbar(void)
{
    int nscroll;

    nscroll = count234(scrollback);

    set_sbar(nscroll + rows, nscroll + disptop, rows);
}

/*
 * Check whether the region bounded by the two pointers intersects
 * the scroll region, and de-select the on-screen selection if so.
 */
static void check_selection(pos from, pos to)
{
    if (poslt(from, selend) && poslt(selstart, to))
        deselect();
}

/*
 * Scroll the screen. (`lines' is +ve for scrolling forward, -ve
 * for backward.) `sb' is TRUE if the scrolling is permitted to
 * affect the scrollback buffer.
 * 
 * NB this function invalidates all pointers into lines of the
 * screen data structures. In particular, you MUST call fix_cpos
 * after calling scroll() and before doing anything else that
 * uses the cpos shortcut pointer.
 */
static void scroll(int topline, int botline, int lines, int sb)
{
    unsigned long *line, *line2;
    int i, seltop;

    if (topline != 0 || alt_which != 0)
        sb = FALSE;

    if (lines < 0) {
        while (lines < 0) {
            line = delpos234(screen, botline);
            line = resizeline(line, cols);
            for (i = 0; i < cols; i++)
                line[i + 1] = erase_char;
            line[cols + 1] = 0;
            addpos234(screen, line, topline);

            if (selstart.y >= topline && selstart.y <= botline) {
                selstart.y++;
                if (selstart.y > botline) {
                    selstart.y = botline;
                    selstart.x = 0;
                }
            }
            if (selend.y >= topline && selend.y <= botline) {
                selend.y++;
                if (selend.y > botline) {
                    selend.y = botline;
                    selend.x = 0;
                }
            }

            lines++;
        }
    } else {
        while (lines > 0) {
            line = delpos234(screen, topline);
            if (sb && savelines > 0) {
                int sblen = count234(scrollback);
                /*
                 * We must add this line to the scrollback. We'll
                 * remove a line from the top of the scrollback to
                 * replace it, or allocate a new one if the
                 * scrollback isn't full.
                 */
                if (sblen == savelines) {
                    sblen--, line2 = delpos234(scrollback, 0);
                } else {
                    line2 = smalloc(TSIZE * (cols + 2));
                    line2[0] = cols;
                }
                addpos234(scrollback, line, sblen);
                line = line2;

                /*
                 * If the user is currently looking at part of the
                 * scrollback, and they haven't enabled any options
                 * that are going to reset the scrollback as a
                 * result of this movement, then the chances are
                 * they'd like to keep looking at the same line. So
                 * we move their viewpoint at the same rate as the
                 * scroll, at least until their viewpoint hits the
                 * top end of the scrollback buffer, at which point
                 * we don't have the choice any more.
                 * 
                 * Thanks to Jan Holmen Holsten for the idea and
                 * initial implementation.
                 */
                if (disptop > -savelines && disptop < 0)
                    disptop--;
            }
            line = resizeline(line, cols);
            for (i = 0; i < cols; i++)
                line[i + 1] = erase_char;
            line[cols + 1] = 0;
            addpos234(screen, line, botline);

            /*
             * If the selection endpoints move into the scrollback,
             * we keep them moving until they hit the top. However,
             * of course, if the line _hasn't_ moved into the
             * scrollback then we don't do this, and cut them off
             * at the top of the scroll region.
             * 
             * This applies to selstart and selend (for an existing
             * selection), and also selanchor (for one being
             * selected as we speak).
             */
            seltop = sb ? -savelines : topline;

            if (selstart.y >= seltop && selstart.y <= botline) {
                selstart.y--;
                if (selstart.y < seltop) {
                    selstart.y = seltop;
                    selstart.x = 0;
                }
            }
            if (selend.y >= seltop && selend.y <= botline) {
                selend.y--;
                if (selend.y < seltop) {
                    selend.y = seltop;
                    selend.x = 0;
                }
            }
            if (selanchor.y >= seltop && selanchor.y <= botline) {
                selanchor.y--;
                if (selanchor.y < seltop) {
                    selanchor.y = seltop;
                    selanchor.x = 0;
                }
            }

            lines--;
        }
    }
}

/*
 * Move the cursor to a given position, clipping at boundaries. We
 * may or may not want to clip at the scroll margin: marg_clip is 0
 * not to, 1 to disallow _passing_ the margins, and 2 to disallow
 * even _being_ outside the margins.
 */
static void move(int x, int y, int marg_clip)
{
    if (x < 0)
        x = 0;
    if (x >= cols)
        x = cols - 1;
    if (marg_clip) {
        if ((curs.y >= marg_t || marg_clip == 2) && y < marg_t)
            y = marg_t;
        if ((curs.y <= marg_b || marg_clip == 2) && y > marg_b)
            y = marg_b;
    }
    if (y < 0)
        y = 0;
    if (y >= rows)
        y = rows - 1;
    curs.x = x;
    curs.y = y;
    fix_cpos;
    wrapnext = FALSE;
}

/*
 * Save or restore the cursor and SGR mode.
 */
static void save_cursor(int save)
{
    if (save) {
        savecurs = curs;
        save_attr = curr_attr;
        save_cset = cset;
        save_utf = utf;
        save_wnext = wrapnext;
        save_csattr = cset_attr[cset];
        save_sco_acs = sco_acs;
    } else {
        curs = savecurs;
        /* Make sure the window hasn't shrunk since the save */
        if (curs.x >= cols)
            curs.x = cols - 1;
        if (curs.y >= rows)
            curs.y = rows - 1;

        curr_attr = save_attr;
        cset = save_cset;
        utf = save_utf;
        wrapnext = save_wnext;
        /*
         * wrapnext might reset to False if the x position is no
         * longer at the rightmost edge.
         */
        if (wrapnext && curs.x < cols-1)
            wrapnext = FALSE;
        cset_attr[cset] = save_csattr;
        sco_acs = save_sco_acs;
        fix_cpos;
        if (use_bce)
            erase_char = (' ' | ATTR_ASCII |
                         (curr_attr & (ATTR_FGMASK | ATTR_BGMASK)));
    }
}

/*
 * Erase a large portion of the screen: the whole screen, or the
 * whole line, or parts thereof.
 */
static void erase_lots(int line_only, int from_begin, int to_end)
{
    pos start, end;
    int erase_lattr;
    unsigned long *ldata;

    if (line_only) {
        start.y = curs.y;
        start.x = 0;
        end.y = curs.y + 1;
        end.x = 0;
        erase_lattr = FALSE;
    } else {
        start.y = 0;
        start.x = 0;
        end.y = rows;
        end.x = 0;
        erase_lattr = TRUE;
    }
    if (!from_begin) {
        start = curs;
    }
    if (!to_end) {
        end = curs;
        incpos(end);
    }
    check_selection(start, end);

    /* Clear screen also forces a full window redraw, just in case. */
    if (start.y == 0 && start.x == 0 && end.y == rows)
        term_invalidate();

    ldata = lineptr(start.y);
    while (poslt(start, end)) {
        if (start.x == cols && !erase_lattr)
            ldata[start.x] &= ~LATTR_WRAPPED;
        else
            ldata[start.x] = erase_char;
        if (incpos(start) && start.y < rows)
            ldata = lineptr(start.y);
    }
}

/*
 * Insert or delete characters within the current line. n is +ve if
 * insertion is desired, and -ve for deletion.
 */
static void insch(int n)
{
    int dir = (n < 0 ? -1 : +1);
    int m;
    pos cursplus;
    unsigned long *ldata;

    n = (n < 0 ? -n : n);
    if (n > cols - curs.x)
        n = cols - curs.x;
    m = cols - curs.x - n;
    cursplus.y = curs.y;
    cursplus.x = curs.x + n;
    check_selection(curs, cursplus);
    ldata = lineptr(curs.y);
    if (dir < 0) {
        memmove(ldata + curs.x, ldata + curs.x + n, m * TSIZE);
        while (n--)
            ldata[curs.x + m++] = erase_char;
    } else {
        memmove(ldata + curs.x + n, ldata + curs.x, m * TSIZE);
        while (n--)
            ldata[curs.x + n] = erase_char;
    }
}

/*
 * Toggle terminal mode `mode' to state `state'. (`query' indicates
 * whether the mode is a DEC private one or a normal one.)
 */
static void toggle_mode(int mode, int query, int state)
{
    unsigned long ticks;

    if (query)
        switch (mode) {
          case 1:                      /* application cursor keys */
            app_cursor_keys = state;
            break;
          case 2:                      /* VT52 mode */
            vt52_mode = !state;
            if (vt52_mode) {
                blink_is_real = FALSE;
                vt52_bold = FALSE;
            } else {
                blink_is_real = cfg.blinktext;
            }
            break;
          case 3:                      /* 80/132 columns */
            deselect();
            if (!cfg.no_remote_resize)
                request_resize(state ? 132 : 80, rows);
            reset_132 = state;
            break;
          case 5:                      /* reverse video */
            /*
             * Toggle reverse video. If we receive an OFF within the
             * visual bell timeout period after an ON, we trigger an
             * effective visual bell, so that ESC[?5hESC[?5l will
             * always be an actually _visible_ visual bell.
             */
            ticks = GETTICKCOUNT();
            /* turn off a previous vbell to avoid inconsistencies */
            if (ticks - vbell_startpoint >= VBELL_TIMEOUT)
                in_vbell = FALSE;
            if (rvideo && !state &&    /* we're turning it off... */
                (ticks - rvbell_startpoint) < VBELL_TIMEOUT) {  /* ...soon */
                /* If there's no vbell timeout already, or this one lasts
                 * longer, replace vbell_timeout with ours. */
                if (!in_vbell ||
                    (rvbell_startpoint - vbell_startpoint < VBELL_TIMEOUT))
                    vbell_startpoint = rvbell_startpoint;
                in_vbell = TRUE;       /* we may clear rvideo but we set in_vbell */
            } else if (!rvideo && state) {
                /* This is an ON, so we notice the time and save it. */
                rvbell_startpoint = ticks;
            }
            rvideo = state;
            seen_disp_event = TRUE;
            if (state)
                term_update();
            break;
          case 6:                      /* DEC origin mode */
            dec_om = state;
            break;
          case 7:                      /* auto wrap */
            wrap = state;
            break;
          case 8:                      /* auto key repeat */
            repeat_off = !state;
            break;
          case 10:                     /* set local edit mode */
            term_editing = state;
            ldisc_send(NULL, 0, 0);    /* cause ldisc to notice changes */
            break;
          case 25:                     /* enable/disable cursor */
            compatibility2(OTHER, VT220);
            cursor_on = state;
            seen_disp_event = TRUE;
            break;
          case 47:                     /* alternate screen */
            compatibility(OTHER);
            deselect();
            swap_screen(cfg.no_alt_screen ? 0 : state, FALSE, FALSE);
            disptop = 0;
            break;
          case 1000:                   /* xterm mouse 1 */
            xterm_mouse = state ? 1 : 0;
            set_raw_mouse_mode(state);
            break;
          case 1002:                   /* xterm mouse 2 */
            xterm_mouse = state ? 2 : 0;
            set_raw_mouse_mode(state);
            break;
          case 1047:                   /* alternate screen */
            compatibility(OTHER);
            deselect();
            swap_screen(cfg.no_alt_screen ? 0 : state, TRUE, TRUE);
            disptop = 0;
            break;
          case 1048:                   /* save/restore cursor */
            save_cursor(state);
            if (!state) seen_disp_event = TRUE;
            break;
          case 1049:                   /* cursor & alternate screen */
            if (state)
                save_cursor(state);
            if (!state) seen_disp_event = TRUE;
            compatibility(OTHER);
            deselect();
            swap_screen(cfg.no_alt_screen ? 0 : state, TRUE, FALSE);
            if (!state)
                save_cursor(state);
            disptop = 0;
            break;
    } else
        switch (mode) {
          case 4:                      /* set insert mode */
            compatibility(VT102);
            insert = state;
            break;
          case 12:                     /* set echo mode */
            term_echoing = !state;
            ldisc_send(NULL, 0, 0);    /* cause ldisc to notice changes */
            break;
          case 20:                     /* Return sends ... */
            cr_lf_return = state;
            break;
          case 34:                     /* Make cursor BIG */
            compatibility2(OTHER, VT220);
            big_cursor = !state;
        }
}

/*
 * Process an OSC sequence: set window title or icon name.
 */
static void do_osc(void)
{
    if (osc_w) {
        while (osc_strlen--)
            wordness[(unsigned char) osc_string[osc_strlen]] = esc_args[0];
    } else {
        osc_string[osc_strlen] = '\0';
        switch (esc_args[0]) {
          case 0:
          case 1:
            if (!cfg.no_remote_wintitle)
                set_icon(osc_string);
            if (esc_args[0] == 1)
                break;
            /* fall through: parameter 0 means set both */
          case 2:
          case 21:
            if (!cfg.no_remote_wintitle)
                set_title(osc_string);
            break;
        }
    }
}

/*
 * ANSI printing routines.
 */
static void term_print_setup(void)
{
    bufchain_clear(&printer_buf);
    print_job = printer_start_job(cfg.printer);
}
static void term_print_flush(void)
{
    void *data;
    int len;
    int size;
    while ((size = bufchain_size(&printer_buf)) > 5) {
        bufchain_prefix(&printer_buf, &data, &len);
        if (len > size-5)
            len = size-5;
        printer_job_data(print_job, data, len);
        bufchain_consume(&printer_buf, len);
    }
}
static void term_print_finish(void)
{
    void *data;
    int len, size;
    char c;

    if (!printing && !only_printing)
        return;                        /* we need do nothing */

    term_print_flush();
    while ((size = bufchain_size(&printer_buf)) > 0) {
        bufchain_prefix(&printer_buf, &data, &len);
        c = *(char *)data;
        if (c == '\033' || c == '\233') {
            bufchain_consume(&printer_buf, size);
            break;
        } else {
            printer_job_data(print_job, &c, 1);
            bufchain_consume(&printer_buf, 1);
        }
    }
    printer_finish_job(print_job);
    print_job = NULL;
    printing = only_printing = FALSE;
}

/*
 * Remove everything currently in `inbuf' and stick it up on the
 * in-memory display. There's a big state machine in here to
 * process escape sequences...
 */
void term_out(void)
{
    int c, unget;
    unsigned char localbuf[256], *chars;
    int nchars = 0;

    unget = -1;

    chars = NULL;                      /* placate compiler warnings */
    while (nchars > 0 || bufchain_size(&inbuf) > 0) {
        if (unget == -1) {
            if (nchars == 0) {
                void *ret;
                bufchain_prefix(&inbuf, &ret, &nchars);
                if (nchars > sizeof(localbuf))
                    nchars = sizeof(localbuf);
                memcpy(localbuf, ret, nchars);
                bufchain_consume(&inbuf, nchars);
                chars = localbuf;
                assert(chars != NULL);
            }
            c = *chars++;
            nchars--;

            /*
             * Optionally log the session traffic to a file. Useful for
             * debugging and possibly also useful for actual logging.
             */
            if (cfg.logtype == LGTYP_DEBUG)
                logtraffic((unsigned char) c, LGTYP_DEBUG);
        } else {
            c = unget;
            unget = -1;
        }

        /* Note only VT220+ are 8-bit VT102 is seven bit, it shouldn't even
         * be able to display 8-bit characters, but I'll let that go 'cause
         * of i18n.
         */

        /*
         * If we're printing, add the character to the printer
         * buffer.
         */
        if (printing) {
            bufchain_add(&printer_buf, &c, 1);

            /*
             * If we're in print-only mode, we use a much simpler
             * state machine designed only to recognise the ESC[4i
             * termination sequence.
             */
            if (only_printing) {
                if (c == '\033')
                    print_state = 1;
                else if (c == (unsigned char)'\233')
                    print_state = 2;
                else if (c == '[' && print_state == 1)
                    print_state = 2;
                else if (c == '4' && print_state == 2)
                    print_state = 3;
                else if (c == 'i' && print_state == 3)
                    print_state = 4;
                else
                    print_state = 0;
                if (print_state == 4) {
                    term_print_finish();
                }
                continue;
            }
        }

        /* First see about all those translations. */
        if (termstate == TOPLEVEL) {
            if (in_utf)
                switch (utf_state) {
                  case 0:
                    if (c < 0x80) {
                        /* UTF-8 must be stateless so we ignore iso2022. */
                        if (unitab_ctrl[c] != 0xFF) 
                             c = unitab_ctrl[c];
                        else c = ((unsigned char)c) | ATTR_ASCII;
                        break;
                    } else if ((c & 0xe0) == 0xc0) {
                        utf_size = utf_state = 1;
                        utf_char = (c & 0x1f);
                    } else if ((c & 0xf0) == 0xe0) {
                        utf_size = utf_state = 2;
                        utf_char = (c & 0x0f);
                    } else if ((c & 0xf8) == 0xf0) {
                        utf_size = utf_state = 3;
                        utf_char = (c & 0x07);
                    } else if ((c & 0xfc) == 0xf8) {
                        utf_size = utf_state = 4;
                        utf_char = (c & 0x03);
                    } else if ((c & 0xfe) == 0xfc) {
                        utf_size = utf_state = 5;
                        utf_char = (c & 0x01);
                    } else {
                        c = UCSERR;
                        break;
                    }
                    continue;
                  case 1:
                  case 2:
                  case 3:
                  case 4:
                  case 5:
                    if ((c & 0xC0) != 0x80) {
                        unget = c;
                        c = UCSERR;
                        utf_state = 0;
                        break;
                    }
                    utf_char = (utf_char << 6) | (c & 0x3f);
                    if (--utf_state)
                        continue;

                    c = utf_char;

                    /* Is somebody trying to be evil! */
                    if (c < 0x80 ||
                        (c < 0x800 && utf_size >= 2) ||
                        (c < 0x10000 && utf_size >= 3) ||
                        (c < 0x200000 && utf_size >= 4) ||
                        (c < 0x4000000 && utf_size >= 5))
                        c = UCSERR;

                    /* Unicode line separator and paragraph separator are CR-LF */
                    if (c == 0x2028 || c == 0x2029)
                        c = 0x85;

                    /* High controls are probably a Baaad idea too. */
                    if (c < 0xA0)
                        c = 0xFFFD;

                    /* The UTF-16 surrogates are not nice either. */
                    /*       The standard give the option of decoding these: 
                     *       I don't want to! */
                    if (c >= 0xD800 && c < 0xE000)
                        c = UCSERR;

                    /* ISO 10646 characters now limited to UTF-16 range. */
                    if (c > 0x10FFFF)
                        c = UCSERR;

                    /* This is currently a TagPhobic application.. */
                    if (c >= 0xE0000 && c <= 0xE007F)
                        continue;

                    /* U+FEFF is best seen as a null. */
                    if (c == 0xFEFF)
                        continue;
                    /* But U+FFFE is an error. */
                    if (c == 0xFFFE || c == 0xFFFF)
                        c = UCSERR;

                    /* Oops this is a 16bit implementation */
                    if (c >= 0x10000)
                        c = 0xFFFD;
                    break;
            }
            /* Are we in the nasty ACS mode? Note: no sco in utf mode. */
            else if(sco_acs && 
                    (c!='\033' && c!='\n' && c!='\r' && c!='\b'))
            {
               if (sco_acs == 2) c ^= 0x80;
               c |= ATTR_SCOACS;
            } else {
                switch (cset_attr[cset]) {
                    /* 
                     * Linedraw characters are different from 'ESC ( B'
                     * only for a small range. For ones outside that
                     * range, make sure we use the same font as well as
                     * the same encoding.
                     */
                  case ATTR_LINEDRW:
                    if (unitab_ctrl[c] != 0xFF)
                        c = unitab_ctrl[c];
                    else
                        c = ((unsigned char) c) | ATTR_LINEDRW;
                    break;

                  case ATTR_GBCHR:
                    /* If UK-ASCII, make the '#' a LineDraw Pound */
                    if (c == '#') {
                        c = '}' | ATTR_LINEDRW;
                        break;
                    }
                  /*FALLTHROUGH*/ case ATTR_ASCII:
                    if (unitab_ctrl[c] != 0xFF)
                        c = unitab_ctrl[c];
                    else
                        c = ((unsigned char) c) | ATTR_ASCII;
                    break;
                case ATTR_SCOACS:
                    if (c>=' ') c = ((unsigned char)c) | ATTR_SCOACS;
                    break;
                }
            }
        }

        /* How about C1 controls ? */
        if ((c & -32) == 0x80 && termstate < DO_CTRLS && !vt52_mode &&
            has_compat(VT220)) {
            termstate = SEEN_ESC;
            esc_query = FALSE;
            c = '@' + (c & 0x1F);
        }

        /* Or the GL control. */
        if (c == '\177' && termstate < DO_CTRLS && has_compat(OTHER)) {
            if (curs.x && !wrapnext)
                curs.x--;
            wrapnext = FALSE;
            fix_cpos;
            if (!cfg.no_dbackspace)    /* destructive bksp might be disabled */
                *cpos = (' ' | curr_attr | ATTR_ASCII);
        } else
            /* Or normal C0 controls. */
        if ((c & -32) == 0 && termstate < DO_CTRLS) {
            switch (c) {
              case '\005':             /* terminal type query */
                /* Strictly speaking this is VT100 but a VT100 defaults to
                 * no response. Other terminals respond at their option.
                 *
                 * Don't put a CR in the default string as this tends to
                 * upset some weird software.
                 *
                 * An xterm returns "xterm" (5 characters)
                 */
                compatibility(ANSIMIN);
                {
                    char abuf[256], *s, *d;
                    int state = 0;
                    for (s = cfg.answerback, d = abuf; *s; s++) {
                        if (state) {
                            if (*s >= 'a' && *s <= 'z')
                                *d++ = (*s - ('a' - 1));
                            else if ((*s >= '@' && *s <= '_') ||
                                     *s == '?' || (*s & 0x80))
                                *d++ = ('@' ^ *s);
                            else if (*s == '~')
                                *d++ = '^';
                            state = 0;
                        } else if (*s == '^') {
                            state = 1;
                        } else
                            *d++ = *s;
                    }
                    lpage_send(DEFAULT_CODEPAGE, abuf, d - abuf, 0);
                }
                break;
              case '\007':
                {
                    struct beeptime *newbeep;
                    unsigned long ticks;

                    ticks = GETTICKCOUNT();

                    if (!beep_overloaded) {
                        newbeep = smalloc(sizeof(struct beeptime));
                        newbeep->ticks = ticks;
                        newbeep->next = NULL;
                        if (!beephead)
                            beephead = newbeep;
                        else
                            beeptail->next = newbeep;
                        beeptail = newbeep;
                        nbeeps++;
                    }

                    /*
                     * Throw out any beeps that happened more than
                     * t seconds ago.
                     */
                    while (beephead &&
                           beephead->ticks < ticks - cfg.bellovl_t) {
                        struct beeptime *tmp = beephead;
                        beephead = tmp->next;
                        sfree(tmp);
                        if (!beephead)
                            beeptail = NULL;
                        nbeeps--;
                    }

                    if (cfg.bellovl && beep_overloaded &&
                        ticks - lastbeep >= (unsigned)cfg.bellovl_s) {
                        /*
                         * If we're currently overloaded and the
                         * last beep was more than s seconds ago,
                         * leave overload mode.
                         */
                        beep_overloaded = FALSE;
                    } else if (cfg.bellovl && !beep_overloaded &&
                               nbeeps >= cfg.bellovl_n) {
                        /*
                         * Now, if we have n or more beeps
                         * remaining in the queue, go into overload
                         * mode.
                         */
                        beep_overloaded = TRUE;
                    }
                    lastbeep = ticks;

                    /*
                     * Perform an actual beep if we're not overloaded.
                     */
                    if (!cfg.bellovl || !beep_overloaded) {
                        if (cfg.beep == BELL_VISUAL) {
                            in_vbell = TRUE;
                            vbell_startpoint = ticks;
                            term_update();
                        } else
                            beep(cfg.beep);
                    }
                    disptop = 0;
                }
                break;
              case '\b':
                if (curs.x == 0 && (curs.y == 0 || wrap == 0));
                else if (curs.x == 0 && curs.y > 0)
                    curs.x = cols - 1, curs.y--;
                else if (wrapnext)
                    wrapnext = FALSE;
                else
                    curs.x--;
                fix_cpos;
                seen_disp_event = TRUE;
                break;
              case '\016':
                compatibility(VT100);
                cset = 1;
                break;
              case '\017':
                compatibility(VT100);
                cset = 0;
                break;
              case '\033':
                if (vt52_mode)
                    termstate = VT52_ESC;
                else {
                    compatibility(ANSIMIN);
                    termstate = SEEN_ESC;
                    esc_query = FALSE;
                }
                break;
              case '\r':
                curs.x = 0;
                wrapnext = FALSE;
                fix_cpos;
                seen_disp_event = TRUE;
                paste_hold = 0;
                logtraffic((unsigned char) c, LGTYP_ASCII);
                break;
              case '\014':
                if (has_compat(SCOANSI)) {
                    move(0, 0, 0);
                    erase_lots(FALSE, FALSE, TRUE);
                    disptop = 0;
                    wrapnext = FALSE;
                    seen_disp_event = 1;
                    break;
                }
              case '\013':
                compatibility(VT100);
              case '\n':
                if (curs.y == marg_b)
                    scroll(marg_t, marg_b, 1, TRUE);
                else if (curs.y < rows - 1)
                    curs.y++;
                if (cfg.lfhascr)
                    curs.x = 0;
                fix_cpos;
                wrapnext = FALSE;
                seen_disp_event = 1;
                paste_hold = 0;
                logtraffic((unsigned char) c, LGTYP_ASCII);
                break;
              case '\t':
                {
                    pos old_curs = curs;
                    unsigned long *ldata = lineptr(curs.y);

                    do {
                        curs.x++;
                    } while (curs.x < cols - 1 && !tabs[curs.x]);

                    if ((ldata[cols] & LATTR_MODE) != LATTR_NORM) {
                        if (curs.x >= cols / 2)
                            curs.x = cols / 2 - 1;
                    } else {
                        if (curs.x >= cols)
                            curs.x = cols - 1;
                    }

                    fix_cpos;
                    check_selection(old_curs, curs);
                }
                seen_disp_event = TRUE;
                break;
            }
        } else
            switch (termstate) {
              case TOPLEVEL:
                /* Only graphic characters get this far, ctrls are stripped above */
                if (wrapnext && wrap) {
                    cpos[1] |= LATTR_WRAPPED;
                    if (curs.y == marg_b)
                        scroll(marg_t, marg_b, 1, TRUE);
                    else if (curs.y < rows - 1)
                        curs.y++;
                    curs.x = 0;
                    fix_cpos;
                    wrapnext = FALSE;
                }
                if (insert)
                    insch(1);
                if (selstate != NO_SELECTION) {
                    pos cursplus = curs;
                    incpos(cursplus);
                    check_selection(curs, cursplus);
                }
                if ((c & CSET_MASK) == ATTR_ASCII || (c & CSET_MASK) == 0)
                    logtraffic((unsigned char) c, LGTYP_ASCII);
                {
                    extern int wcwidth(wchar_t ucs);
                    int width = 0;
                    if (DIRECT_CHAR(c))
                        width = 1;
                    if (!width)
                        width = wcwidth((wchar_t) c);
                    switch (width) {
                      case 2:
                        *cpos++ = c | curr_attr;
                        if (++curs.x == cols) {
                            *cpos |= LATTR_WRAPPED;
                            if (curs.y == marg_b)
                                scroll(marg_t, marg_b, 1, TRUE);
                            else if (curs.y < rows - 1)
                                curs.y++;
                            curs.x = 0;
                            fix_cpos;
                        }
                        *cpos++ = UCSWIDE | curr_attr;
                        break;
                      case 1:
                        *cpos++ = c | curr_attr;
                        break;
                      default:
                        continue;
                    }
                }
                curs.x++;
                if (curs.x == cols) {
                    cpos--;
                    curs.x--;
                    wrapnext = TRUE;
                    if (wrap && vt52_mode) {
                        cpos[1] |= LATTR_WRAPPED;
                        if (curs.y == marg_b)
                            scroll(marg_t, marg_b, 1, TRUE);
                        else if (curs.y < rows - 1)
                            curs.y++;
                        curs.x = 0;
                        fix_cpos;
                        wrapnext = FALSE;
                    }
                }
                seen_disp_event = 1;
                break;

              case OSC_MAYBE_ST:
                /*
                 * This state is virtually identical to SEEN_ESC, with the
                 * exception that we have an OSC sequence in the pipeline,
                 * and _if_ we see a backslash, we process it.
                 */
                if (c == '\\') {
                    do_osc();
                    termstate = TOPLEVEL;
                    break;
                }
                /* else fall through */
              case SEEN_ESC:
                if (c >= ' ' && c <= '/') {
                    if (esc_query)
                        esc_query = -1;
                    else
                        esc_query = c;
                    break;
                }
                termstate = TOPLEVEL;
                switch (ANSI(c, esc_query)) {
                  case '[':            /* enter CSI mode */
                    termstate = SEEN_CSI;
                    esc_nargs = 1;
                    esc_args[0] = ARG_DEFAULT;
                    esc_query = FALSE;
                    break;
                  case ']':            /* xterm escape sequences */
                    /* Compatibility is nasty here, xterm, linux, decterm yuk! */
                    compatibility(OTHER);
                    termstate = SEEN_OSC;
                    esc_args[0] = 0;
                    break;
                  case '7':            /* save cursor */
                    compatibility(VT100);
                    save_cursor(TRUE);
                    break;
                  case '8':            /* restore cursor */
                    compatibility(VT100);
                    save_cursor(FALSE);
                    seen_disp_event = TRUE;
                    break;
                  case '=':
                    compatibility(VT100);
                    app_keypad_keys = TRUE;
                    break;
                  case '>':
                    compatibility(VT100);
                    app_keypad_keys = FALSE;
                    break;
                  case 'D':            /* exactly equivalent to LF */
                    compatibility(VT100);
                    if (curs.y == marg_b)
                        scroll(marg_t, marg_b, 1, TRUE);
                    else if (curs.y < rows - 1)
                        curs.y++;
                    fix_cpos;
                    wrapnext = FALSE;
                    seen_disp_event = TRUE;
                    break;
                  case 'E':            /* exactly equivalent to CR-LF */
                    compatibility(VT100);
                    curs.x = 0;
                    if (curs.y == marg_b)
                        scroll(marg_t, marg_b, 1, TRUE);
                    else if (curs.y < rows - 1)
                        curs.y++;
                    fix_cpos;
                    wrapnext = FALSE;
                    seen_disp_event = TRUE;
                    break;
                  case 'M':            /* reverse index - backwards LF */
                    compatibility(VT100);
                    if (curs.y == marg_t)
                        scroll(marg_t, marg_b, -1, TRUE);
                    else if (curs.y > 0)
                        curs.y--;
                    fix_cpos;
                    wrapnext = FALSE;
                    seen_disp_event = TRUE;
                    break;
                  case 'Z':            /* terminal type query */
                    compatibility(VT100);
                    ldisc_send(id_string, strlen(id_string), 0);
                    break;
                  case 'c':            /* restore power-on settings */
                    compatibility(VT100);
                    power_on();
                    if (reset_132) {
                        if (!cfg.no_remote_resize)
                            request_resize(80, rows);
                        reset_132 = 0;
                    }
                    fix_cpos;
                    disptop = 0;
                    seen_disp_event = TRUE;
                    break;
                  case 'H':            /* set a tab */
                    compatibility(VT100);
                    tabs[curs.x] = TRUE;
                    break;

                  case ANSI('8', '#'):  /* ESC # 8 fills screen with Es :-) */
                    compatibility(VT100);
                    {
                        unsigned long *ldata;
                        int i, j;
                        pos scrtop, scrbot;

                        for (i = 0; i < rows; i++) {
                            ldata = lineptr(i);
                            for (j = 0; j < cols; j++)
                                ldata[j] = ATTR_DEFAULT | 'E';
                            ldata[cols] = 0;
                        }
                        disptop = 0;
                        seen_disp_event = TRUE;
                        scrtop.x = scrtop.y = 0;
                        scrbot.x = 0;
                        scrbot.y = rows;
                        check_selection(scrtop, scrbot);
                    }
                    break;

                  case ANSI('3', '#'):
                  case ANSI('4', '#'):
                  case ANSI('5', '#'):
                  case ANSI('6', '#'):
                    compatibility(VT100);
                    {
                        unsigned long nlattr;
                        unsigned long *ldata;
                        switch (ANSI(c, esc_query)) {
                          case ANSI('3', '#'):
                            nlattr = LATTR_TOP;
                            break;
                          case ANSI('4', '#'):
                            nlattr = LATTR_BOT;
                            break;
                          case ANSI('5', '#'):
                            nlattr = LATTR_NORM;
                            break;
                          default: /* spiritually case ANSI('6', '#'): */
                            nlattr = LATTR_WIDE;
                            break;
                        }
                        ldata = lineptr(curs.y);
                        ldata[cols] &= ~LATTR_MODE;
                        ldata[cols] |= nlattr;
                    }
                    break;

                  case ANSI('A', '('):
                    compatibility(VT100);
                    if (!cfg.no_remote_charset)
                        cset_attr[0] = ATTR_GBCHR;
                    break;
                  case ANSI('B', '('):
                    compatibility(VT100);
                    if (!cfg.no_remote_charset)
                        cset_attr[0] = ATTR_ASCII;
                    break;
                  case ANSI('0', '('):
                    compatibility(VT100);
                    if (!cfg.no_remote_charset)
                        cset_attr[0] = ATTR_LINEDRW;
                    break;
                  case ANSI('U', '('): 
                    compatibility(OTHER);
                    if (!cfg.no_remote_charset)
                        cset_attr[0] = ATTR_SCOACS; 
                    break;

                  case ANSI('A', ')'):
                    compatibility(VT100);
                    if (!cfg.no_remote_charset)
                        cset_attr[1] = ATTR_GBCHR;
                    break;
                  case ANSI('B', ')'):
                    compatibility(VT100);
                    if (!cfg.no_remote_charset)
                        cset_attr[1] = ATTR_ASCII;
                    break;
                  case ANSI('0', ')'):
                    compatibility(VT100);
                    if (!cfg.no_remote_charset)
                        cset_attr[1] = ATTR_LINEDRW;
                    break;
                  case ANSI('U', ')'): 
                    compatibility(OTHER);
                    if (!cfg.no_remote_charset)
                        cset_attr[1] = ATTR_SCOACS; 
                    break;

                  case ANSI('8', '%'):  /* Old Linux code */
                  case ANSI('G', '%'):
                    compatibility(OTHER);
                    if (!cfg.no_remote_charset)
                        utf = 1;
                    break;
                  case ANSI('@', '%'):
                    compatibility(OTHER);
                    if (!cfg.no_remote_charset)
                        utf = 0;
                    break;
                }
                break;
              case SEEN_CSI:
                termstate = TOPLEVEL;  /* default */
                if (isdigit(c)) {
                    if (esc_nargs <= ARGS_MAX) {
                        if (esc_args[esc_nargs - 1] == ARG_DEFAULT)
                            esc_args[esc_nargs - 1] = 0;
                        esc_args[esc_nargs - 1] =
                            10 * esc_args[esc_nargs - 1] + c - '0';
                    }
                    termstate = SEEN_CSI;
                } else if (c == ';') {
                    if (++esc_nargs <= ARGS_MAX)
                        esc_args[esc_nargs - 1] = ARG_DEFAULT;
                    termstate = SEEN_CSI;
                } else if (c < '@') {
                    if (esc_query)
                        esc_query = -1;
                    else if (c == '?')
                        esc_query = TRUE;
                    else
                        esc_query = c;
                    termstate = SEEN_CSI;
                } else
                    switch (ANSI(c, esc_query)) {
                      case 'A':       /* move up N lines */
                        move(curs.x, curs.y - def(esc_args[0], 1), 1);
                        seen_disp_event = TRUE;
                        break;
                      case 'e':       /* move down N lines */
                        compatibility(ANSI);
                        /* FALLTHROUGH */
                      case 'B':
                        move(curs.x, curs.y + def(esc_args[0], 1), 1);
                        seen_disp_event = TRUE;
                        break;
                      case ANSI('c', '>'):      /* report xterm version */
                        compatibility(OTHER);
                        /* this reports xterm version 136 so that VIM can
                           use the drag messages from the mouse reporting */
                        ldisc_send("\033[>0;136;0c", 11, 0);
                        break;
                      case 'a':       /* move right N cols */
                        compatibility(ANSI);
                        /* FALLTHROUGH */
                      case 'C':
                        move(curs.x + def(esc_args[0], 1), curs.y, 1);
                        seen_disp_event = TRUE;
                        break;
                      case 'D':       /* move left N cols */
                        move(curs.x - def(esc_args[0], 1), curs.y, 1);
                        seen_disp_event = TRUE;
                        break;
                      case 'E':       /* move down N lines and CR */
                        compatibility(ANSI);
                        move(0, curs.y + def(esc_args[0], 1), 1);
                        seen_disp_event = TRUE;
                        break;
                      case 'F':       /* move up N lines and CR */
                        compatibility(ANSI);
                        move(0, curs.y - def(esc_args[0], 1), 1);
                        seen_disp_event = TRUE;
                        break;
                      case 'G':
                      case '`':       /* set horizontal posn */
                        compatibility(ANSI);
                        move(def(esc_args[0], 1) - 1, curs.y, 0);
                        seen_disp_event = TRUE;
                        break;
                      case 'd':       /* set vertical posn */
                        compatibility(ANSI);
                        move(curs.x,
                             (dec_om ? marg_t : 0) + def(esc_args[0],
                                                         1) - 1,
                             (dec_om ? 2 : 0));
                        seen_disp_event = TRUE;
                        break;
                      case 'H':
                      case 'f':       /* set horz and vert posns at once */
                        if (esc_nargs < 2)
                            esc_args[1] = ARG_DEFAULT;
                        move(def(esc_args[1], 1) - 1,
                             (dec_om ? marg_t : 0) + def(esc_args[0],
                                                         1) - 1,
                             (dec_om ? 2 : 0));
                        seen_disp_event = TRUE;
                        break;
                      case 'J':       /* erase screen or parts of it */
                        {
                            unsigned int i = def(esc_args[0], 0) + 1;
                            if (i > 3)
                                i = 0;
                            erase_lots(FALSE, !!(i & 2), !!(i & 1));
                        }
                        disptop = 0;
                        seen_disp_event = TRUE;
                        break;
                      case 'K':       /* erase line or parts of it */
                        {
                            unsigned int i = def(esc_args[0], 0) + 1;
                            if (i > 3)
                                i = 0;
                            erase_lots(TRUE, !!(i & 2), !!(i & 1));
                        }
                        seen_disp_event = TRUE;
                        break;
                      case 'L':       /* insert lines */
                        compatibility(VT102);
                        if (curs.y <= marg_b)
                            scroll(curs.y, marg_b, -def(esc_args[0], 1),
                                   FALSE);
                        fix_cpos;
                        seen_disp_event = TRUE;
                        break;
                      case 'M':       /* delete lines */
                        compatibility(VT102);
                        if (curs.y <= marg_b)
                            scroll(curs.y, marg_b, def(esc_args[0], 1),
                                   TRUE);
                        fix_cpos;
                        seen_disp_event = TRUE;
                        break;
                      case '@':       /* insert chars */
                        /* XXX VTTEST says this is vt220, vt510 manual says vt102 */
                        compatibility(VT102);
                        insch(def(esc_args[0], 1));
                        seen_disp_event = TRUE;
                        break;
                      case 'P':       /* delete chars */
                        compatibility(VT102);
                        insch(-def(esc_args[0], 1));
                        seen_disp_event = TRUE;
                        break;
                      case 'c':       /* terminal type query */
                        compatibility(VT100);
                        /* This is the response for a VT102 */
                        ldisc_send(id_string, strlen(id_string), 0);
                        break;
                      case 'n':       /* cursor position query */
                        if (esc_args[0] == 6) {
                            char buf[32];
                            sprintf(buf, "\033[%d;%dR", curs.y + 1,
                                    curs.x + 1);
                            ldisc_send(buf, strlen(buf), 0);
                        } else if (esc_args[0] == 5) {
                            ldisc_send("\033[0n", 4, 0);
                        }
                        break;
                      case 'h':       /* toggle modes to high */
                      case ANSI_QUE('h'):
                        compatibility(VT100);
                        {
                            int i;
                            for (i = 0; i < esc_nargs; i++)
                                toggle_mode(esc_args[i], esc_query, TRUE);
                        }
                        break;
                      case 'i':
                      case ANSI_QUE('i'):
                        compatibility(VT100);
                        {
                            if (esc_nargs != 1) break;
                            if (esc_args[0] == 5 && *cfg.printer) {
                                printing = TRUE;
                                only_printing = !esc_query;
                                print_state = 0;
                                term_print_setup();
                            } else if (esc_args[0] == 4 && printing) {
                                term_print_finish();
                            }
                        }
                        break;                  
                      case 'l':       /* toggle modes to low */
                      case ANSI_QUE('l'):
                        compatibility(VT100);
                        {
                            int i;
                            for (i = 0; i < esc_nargs; i++)
                                toggle_mode(esc_args[i], esc_query, FALSE);
                        }
                        break;
                      case 'g':       /* clear tabs */
                        compatibility(VT100);
                        if (esc_nargs == 1) {
                            if (esc_args[0] == 0) {
                                tabs[curs.x] = FALSE;
                            } else if (esc_args[0] == 3) {
                                int i;
                                for (i = 0; i < cols; i++)
                                    tabs[i] = FALSE;
                            }
                        }
                        break;
                      case 'r':       /* set scroll margins */
                        compatibility(VT100);
                        if (esc_nargs <= 2) {
                            int top, bot;
                            top = def(esc_args[0], 1) - 1;
                            bot = (esc_nargs <= 1
                                   || esc_args[1] ==
                                   0 ? rows : def(esc_args[1], rows)) - 1;
                            if (bot >= rows)
                                bot = rows - 1;
                            /* VTTEST Bug 9 - if region is less than 2 lines
                             * don't change region.
                             */
                            if (bot - top > 0) {
                                marg_t = top;
                                marg_b = bot;
                                curs.x = 0;
                                /*
                                 * I used to think the cursor should be
                                 * placed at the top of the newly marginned
                                 * area. Apparently not: VMS TPU falls over
                                 * if so.
                                 *
                                 * Well actually it should for Origin mode - RDB
                                 */
                                curs.y = (dec_om ? marg_t : 0);
                                fix_cpos;
                                seen_disp_event = TRUE;
                            }
                        }
                        break;
                      case 'm':       /* set graphics rendition */
                        {
                            /* 
                             * A VT100 without the AVO only had one attribute, either
                             * underline or reverse video depending on the cursor type,
                             * this was selected by CSI 7m.
                             *
                             * case 2:
                             *  This is sometimes DIM, eg on the GIGI and Linux
                             * case 8:
                             *  This is sometimes INVIS various ANSI.
                             * case 21:
                             *  This like 22 disables BOLD, DIM and INVIS
                             *
                             * The ANSI colours appear on any terminal that has colour
                             * (obviously) but the interaction between sgr0 and the
                             * colours varies but is usually related to the background
                             * colour erase item.
                             * The interaction between colour attributes and the mono
                             * ones is also very implementation dependent.
                             *
                             * The 39 and 49 attributes are likely to be unimplemented.
                             */
                            int i;
                            for (i = 0; i < esc_nargs; i++) {
                                switch (def(esc_args[i], 0)) {
                                  case 0:       /* restore defaults */
                                    curr_attr = ATTR_DEFAULT;
                                    break;
                                  case 1:       /* enable bold */
                                    compatibility(VT100AVO);
                                    curr_attr |= ATTR_BOLD;
                                    break;
                                  case 21:      /* (enable double underline) */
                                    compatibility(OTHER);
                                  case 4:       /* enable underline */
                                    compatibility(VT100AVO);
                                    curr_attr |= ATTR_UNDER;
                                    break;
                                  case 5:       /* enable blink */
                                    compatibility(VT100AVO);
                                    curr_attr |= ATTR_BLINK;
                                    break;
                                  case 7:       /* enable reverse video */
                                    curr_attr |= ATTR_REVERSE;
                                    break;
                                  case 10:      /* SCO acs off */
                                    compatibility(SCOANSI);
                                    if (cfg.no_remote_charset) break;
                                    sco_acs = 0; break;
                                  case 11:      /* SCO acs on */
                                    compatibility(SCOANSI);
                                    if (cfg.no_remote_charset) break;
                                    sco_acs = 1; break;
                                  case 12:      /* SCO acs on flipped */
                                    compatibility(SCOANSI);
                                    if (cfg.no_remote_charset) break;
                                    sco_acs = 2; break;
                                  case 22:      /* disable bold */
                                    compatibility2(OTHER, VT220);
                                    curr_attr &= ~ATTR_BOLD;
                                    break;
                                  case 24:      /* disable underline */
                                    compatibility2(OTHER, VT220);
                                    curr_attr &= ~ATTR_UNDER;
                                    break;
                                  case 25:      /* disable blink */
                                    compatibility2(OTHER, VT220);
                                    curr_attr &= ~ATTR_BLINK;
                                    break;
                                  case 27:      /* disable reverse video */
                                    compatibility2(OTHER, VT220);
                                    curr_attr &= ~ATTR_REVERSE;
                                    break;
                                  case 30:
                                  case 31:
                                  case 32:
                                  case 33:
                                  case 34:
                                  case 35:
                                  case 36:
                                  case 37:
                                    /* foreground */
                                    curr_attr &= ~ATTR_FGMASK;
                                    curr_attr |=
                                        (esc_args[i] - 30) << ATTR_FGSHIFT;
                                    break;
                                  case 39:      /* default-foreground */
                                    curr_attr &= ~ATTR_FGMASK;
                                    curr_attr |= ATTR_DEFFG;
                                    break;
                                  case 40:
                                  case 41:
                                  case 42:
                                  case 43:
                                  case 44:
                                  case 45:
                                  case 46:
                                  case 47:
                                    /* background */
                                    curr_attr &= ~ATTR_BGMASK;
                                    curr_attr |=
                                        (esc_args[i] - 40) << ATTR_BGSHIFT;
                                    break;
                                  case 49:      /* default-background */
                                    curr_attr &= ~ATTR_BGMASK;
                                    curr_attr |= ATTR_DEFBG;
                                    break;
                                }
                            }
                            if (use_bce)
                                erase_char = (' ' | ATTR_ASCII |
                                             (curr_attr & 
                                              (ATTR_FGMASK | ATTR_BGMASK)));
                        }
                        break;
                      case 's':       /* save cursor */
                        save_cursor(TRUE);
                        break;
                      case 'u':       /* restore cursor */
                        save_cursor(FALSE);
                        seen_disp_event = TRUE;
                        break;
                      case 't':       /* set page size - ie window height */
                        /*
                         * VT340/VT420 sequence DECSLPP, DEC only allows values
                         *  24/25/36/48/72/144 other emulators (eg dtterm) use
                         * illegal values (eg first arg 1..9) for window changing 
                         * and reports.
                         */
                        if (esc_nargs <= 1
                            && (esc_args[0] < 1 || esc_args[0] >= 24)) {
                            compatibility(VT340TEXT);
                            if (!cfg.no_remote_resize)
                                request_resize(cols, def(esc_args[0], 24));
                            deselect();
                        } else if (esc_nargs >= 1 &&
                                   esc_args[0] >= 1 &&
                                   esc_args[0] < 24) {
                            compatibility(OTHER);

                            switch (esc_args[0]) {
                                int x, y, len;
                                char buf[80], *p;
                              case 1:
                                set_iconic(FALSE);
                                break;
                              case 2:
                                set_iconic(TRUE);
                                break;
                              case 3:
                                if (esc_nargs >= 3) {
                                    if (!cfg.no_remote_resize)
                                        move_window(def(esc_args[1], 0),
                                                    def(esc_args[2], 0));
                                }
                                break;
                              case 4:
                                /* We should resize the window to a given
                                 * size in pixels here, but currently our
                                 * resizing code isn't healthy enough to
                                 * manage it. */
                                break;
                              case 5:
                                set_zorder(TRUE);   /* move to top */
                                break;
                              case 6:
                                set_zorder(FALSE);  /* move to bottom */
                                break;
                              case 7:
                                refresh_window();
                                break;
                              case 8:
                                if (esc_nargs >= 3) {
                                    if (!cfg.no_remote_resize)
                                        request_resize(def(esc_args[2], cfg.width),
                                                       def(esc_args[1], cfg.height));
                                }
                                break;
                              case 9:
                                if (esc_nargs >= 2)
                                    set_zoomed(esc_args[1] ? TRUE : FALSE);
                                break;
                              case 11:
                                ldisc_send(is_iconic() ? "\033[1t" : "\033[2t",
                                           4, 0);
                                break;
                              case 13:
                                get_window_pos(&x, &y);
                                len = sprintf(buf, "\033[3;%d;%dt", x, y);
                                ldisc_send(buf, len, 0);
                                break;
                              case 14:
                                get_window_pixels(&x, &y);
                                len = sprintf(buf, "\033[4;%d;%dt", x, y);
                                ldisc_send(buf, len, 0);
                                break;
                              case 18:
                                len = sprintf(buf, "\033[8;%d;%dt",
                                              rows, cols);
                                ldisc_send(buf, len, 0);
                                break;
                              case 19:
                                /*
                                 * Hmmm. Strictly speaking we
                                 * should return `the size of the
                                 * screen in characters', but
                                 * that's not easy: (a) window
                                 * furniture being what it is it's
                                 * hard to compute, and (b) in
                                 * resize-font mode maximising the
                                 * window wouldn't change the
                                 * number of characters. *shrug*. I
                                 * think we'll ignore it for the
                                 * moment and see if anyone
                                 * complains, and then ask them
                                 * what they would like it to do.
                                 */
                                break;
                              case 20:
                                p = get_window_title(TRUE);
                                len = strlen(p);
                                ldisc_send("\033]L", 3, 0);
                                ldisc_send(p, len, 0);
                                ldisc_send("\033\\", 2, 0);
                                break;
                              case 21:
                                p = get_window_title(FALSE);
                                len = strlen(p);
                                ldisc_send("\033]l", 3, 0);
                                ldisc_send(p, len, 0);
                                ldisc_send("\033\\", 2, 0);
                                break;
                            }
                        }
                        break;
                      case 'S':
                        compatibility(SCOANSI);
                        scroll(marg_t, marg_b, def(esc_args[0], 1), TRUE);
                        fix_cpos;
                        wrapnext = FALSE;
                        seen_disp_event = TRUE;
                        break;
                      case 'T':
                        compatibility(SCOANSI);
                        scroll(marg_t, marg_b, -def(esc_args[0], 1), TRUE);
                        fix_cpos;
                        wrapnext = FALSE;
                        seen_disp_event = TRUE;
                        break;
                      case ANSI('|', '*'):
                        /* VT420 sequence DECSNLS
                         * Set number of lines on screen
                         * VT420 uses VGA like hardware and can support any size in
                         * reasonable range (24..49 AIUI) with no default specified.
                         */
                        compatibility(VT420);
                        if (esc_nargs == 1 && esc_args[0] > 0) {
                            if (!cfg.no_remote_resize)
                                request_resize(cols, def(esc_args[0], cfg.height));
                            deselect();
                        }
                        break;
                      case ANSI('|', '$'):
                        /* VT340/VT420 sequence DECSCPP
                         * Set number of columns per page
                         * Docs imply range is only 80 or 132, but I'll allow any.
                         */
                        compatibility(VT340TEXT);
                        if (esc_nargs <= 1) {
                            if (!cfg.no_remote_resize)
                                request_resize(def(esc_args[0], cfg.width), rows);
                            deselect();
                        }
                        break;
                      case 'X':       /* write N spaces w/o moving cursor */
                        /* XXX VTTEST says this is vt220, vt510 manual says vt100 */
                        compatibility(ANSIMIN);
                        {
                            int n = def(esc_args[0], 1);
                            pos cursplus;
                            unsigned long *p = cpos;
                            if (n > cols - curs.x)
                                n = cols - curs.x;
                            cursplus = curs;
                            cursplus.x += n;
                            check_selection(curs, cursplus);
                            while (n--)
                                *p++ = erase_char;
                            seen_disp_event = TRUE;
                        }
                        break;
                      case 'x':       /* report terminal characteristics */
                        compatibility(VT100);
                        {
                            char buf[32];
                            int i = def(esc_args[0], 0);
                            if (i == 0 || i == 1) {
                                strcpy(buf, "\033[2;1;1;112;112;1;0x");
                                buf[2] += i;
                                ldisc_send(buf, 20, 0);
                            }
                        }
                        break;
                      case 'Z':         /* BackTab for xterm */
                        compatibility(OTHER);
                        {
                            int i = def(esc_args[0], 1);
                            pos old_curs = curs;

                            for(;i>0 && curs.x>0; i--) {
                                do {
                                    curs.x--;
                                } while (curs.x >0 && !tabs[curs.x]);
                            }
                            fix_cpos;
                            check_selection(old_curs, curs);
                        }
                        break;
                      case ANSI('L', '='):
                        compatibility(OTHER);
                        use_bce = (esc_args[0] <= 0);
                        erase_char = ERASE_CHAR;
                        if (use_bce)
                            erase_char = (' ' | ATTR_ASCII |
                                         (curr_attr & 
                                          (ATTR_FGMASK | ATTR_BGMASK)));
                        break;
                      case ANSI('E', '='):
                        compatibility(OTHER);
                        blink_is_real = (esc_args[0] >= 1);
                        break;
                      case ANSI('p', '"'):
                        /* Allow the host to make this emulator a 'perfect' VT102.
                         * This first appeared in the VT220, but we do need to get 
                         * back to PuTTY mode so I won't check it.
                         *
                         * The arg in 40..42,50 are a PuTTY extension.
                         * The 2nd arg, 8bit vs 7bit is not checked.
                         *
                         * Setting VT102 mode should also change the Fkeys to
                         * generate PF* codes as a real VT102 has no Fkeys.
                         * The VT220 does this, F11..F13 become ESC,BS,LF other Fkeys
                         * send nothing.
                         *
                         * Note ESC c will NOT change this!
                         */

                        switch (esc_args[0]) {
                          case 61:
                            compatibility_level &= ~TM_VTXXX;
                            compatibility_level |= TM_VT102;
                            break;
                          case 62:
                            compatibility_level &= ~TM_VTXXX;
                            compatibility_level |= TM_VT220;
                            break;

                          default:
                            if (esc_args[0] > 60 && esc_args[0] < 70)
                                compatibility_level |= TM_VTXXX;
                            break;

                          case 40:
                            compatibility_level &= TM_VTXXX;
                            break;
                          case 41:
                            compatibility_level = TM_PUTTY;
                            break;
                          case 42:
                            compatibility_level = TM_SCOANSI;
                            break;

                          case ARG_DEFAULT:
                            compatibility_level = TM_PUTTY;
                            break;
                          case 50:
                            break;
                        }

                        /* Change the response to CSI c */
                        if (esc_args[0] == 50) {
                            int i;
                            char lbuf[64];
                            strcpy(id_string, "\033[?");
                            for (i = 1; i < esc_nargs; i++) {
                                if (i != 1)
                                    strcat(id_string, ";");
                                sprintf(lbuf, "%d", esc_args[i]);
                                strcat(id_string, lbuf);
                            }
                            strcat(id_string, "c");
                        }
#if 0
                        /* Is this a good idea ? 
                         * Well we should do a soft reset at this point ...
                         */
                        if (!has_compat(VT420) && has_compat(VT100)) {
                            if (!cfg.no_remote_resize) {
                                if (reset_132)
                                    request_resize(132, 24);
                                else
                                    request_resize(80, 24);
                            }
                        }
#endif
                        break;
                    }
                break;
              case SEEN_OSC:
                osc_w = FALSE;
                switch (c) {
                  case 'P':            /* Linux palette sequence */
                    termstate = SEEN_OSC_P;
                    osc_strlen = 0;
                    break;
                  case 'R':            /* Linux palette reset */
                    palette_reset();
                    term_invalidate();
                    termstate = TOPLEVEL;
                    break;
                  case 'W':            /* word-set */
                    termstate = SEEN_OSC_W;
                    osc_w = TRUE;
                    break;
                  case '0':
                  case '1':
                  case '2':
                  case '3':
                  case '4':
                  case '5':
                  case '6':
                  case '7':
                  case '8':
                  case '9':
                    esc_args[0] = 10 * esc_args[0] + c - '0';
                    break;
                  case 'L':
                    /*
                     * Grotty hack to support xterm and DECterm title
                     * sequences concurrently.
                     */
                    if (esc_args[0] == 2) {
                        esc_args[0] = 1;
                        break;
                    }
                    /* else fall through */
                  default:
                    termstate = OSC_STRING;
                    osc_strlen = 0;
                }
                break;
              case OSC_STRING:
                /*
                 * This OSC stuff is EVIL. It takes just one character to get into
                 * sysline mode and it's not initially obvious how to get out.
                 * So I've added CR and LF as string aborts.
                 * This shouldn't effect compatibility as I believe embedded 
                 * control characters are supposed to be interpreted (maybe?) 
                 * and they don't display anything useful anyway.
                 *
                 * -- RDB
                 */
                if (c == '\n' || c == '\r') {
                    termstate = TOPLEVEL;
                } else if (c == 0234 || c == '\007') {
                    /*
                     * These characters terminate the string; ST and BEL
                     * terminate the sequence and trigger instant
                     * processing of it, whereas ESC goes back to SEEN_ESC
                     * mode unless it is followed by \, in which case it is
                     * synonymous with ST in the first place.
                     */
                    do_osc();
                    termstate = TOPLEVEL;
                } else if (c == '\033')
                    termstate = OSC_MAYBE_ST;
                else if (osc_strlen < OSC_STR_MAX)
                    osc_string[osc_strlen++] = c;
                break;
              case SEEN_OSC_P:
                {
                    int max = (osc_strlen == 0 ? 21 : 16);
                    int val;
                    if (c >= '0' && c <= '9')
                        val = c - '0';
                    else if (c >= 'A' && c <= 'A' + max - 10)
                        val = c - 'A' + 10;
                    else if (c >= 'a' && c <= 'a' + max - 10)
                        val = c - 'a' + 10;
                    else {
                        termstate = TOPLEVEL;
                        break;
                    }
                    osc_string[osc_strlen++] = val;
                    if (osc_strlen >= 7) {
                        palette_set(osc_string[0],
                                    osc_string[1] * 16 + osc_string[2],
                                    osc_string[3] * 16 + osc_string[4],
                                    osc_string[5] * 16 + osc_string[6]);
                        term_invalidate();
                        termstate = TOPLEVEL;
                    }
                }
                break;
              case SEEN_OSC_W:
                switch (c) {
                  case '0':
                  case '1':
                  case '2':
                  case '3':
                  case '4':
                  case '5':
                  case '6':
                  case '7':
                  case '8':
                  case '9':
                    esc_args[0] = 10 * esc_args[0] + c - '0';
                    break;
                  default:
                    termstate = OSC_STRING;
                    osc_strlen = 0;
                }
                break;
              case VT52_ESC:
                termstate = TOPLEVEL;
                seen_disp_event = TRUE;
                switch (c) {
                  case 'A':
                    move(curs.x, curs.y - 1, 1);
                    break;
                  case 'B':
                    move(curs.x, curs.y + 1, 1);
                    break;
                  case 'C':
                    move(curs.x + 1, curs.y, 1);
                    break;
                  case 'D':
                    move(curs.x - 1, curs.y, 1);
                    break;
                    /*
                     * From the VT100 Manual
                     * NOTE: The special graphics characters in the VT100
                     *       are different from those in the VT52
                     *
                     * From VT102 manual:
                     *       137 _  Blank             - Same
                     *       140 `  Reserved          - Humm.
                     *       141 a  Solid rectangle   - Similar
                     *       142 b  1/                - Top half of fraction for the
                     *       143 c  3/                - subscript numbers below.
                     *       144 d  5/
                     *       145 e  7/
                     *       146 f  Degrees           - Same
                     *       147 g  Plus or minus     - Same
                     *       150 h  Right arrow
                     *       151 i  Ellipsis (dots)
                     *       152 j  Divide by
                     *       153 k  Down arrow
                     *       154 l  Bar at scan 0
                     *       155 m  Bar at scan 1
                     *       156 n  Bar at scan 2
                     *       157 o  Bar at scan 3     - Similar
                     *       160 p  Bar at scan 4     - Similar
                     *       161 q  Bar at scan 5     - Similar
                     *       162 r  Bar at scan 6     - Same
                     *       163 s  Bar at scan 7     - Similar
                     *       164 t  Subscript 0
                     *       165 u  Subscript 1
                     *       166 v  Subscript 2
                     *       167 w  Subscript 3
                     *       170 x  Subscript 4
                     *       171 y  Subscript 5
                     *       172 z  Subscript 6
                     *       173 {  Subscript 7
                     *       174 |  Subscript 8
                     *       175 }  Subscript 9
                     *       176 ~  Paragraph
                     *
                     */
                  case 'F':
                    cset_attr[cset = 0] = ATTR_LINEDRW;
                    break;
                  case 'G':
                    cset_attr[cset = 0] = ATTR_ASCII;
                    break;
                  case 'H':
                    move(0, 0, 0);
                    break;
                  case 'I':
                    if (curs.y == 0)
                        scroll(0, rows - 1, -1, TRUE);
                    else if (curs.y > 0)
                        curs.y--;
                    fix_cpos;
                    wrapnext = FALSE;
                    break;
                  case 'J':
                    erase_lots(FALSE, FALSE, TRUE);
                    disptop = 0;
                    break;
                  case 'K':
                    erase_lots(TRUE, FALSE, TRUE);
                    break;
#if 0
                  case 'V':
                    /* XXX Print cursor line */
                    break;
                  case 'W':
                    /* XXX Start controller mode */
                    break;
                  case 'X':
                    /* XXX Stop controller mode */
                    break;
#endif
                  case 'Y':
                    termstate = VT52_Y1;
                    break;
                  case 'Z':
                    ldisc_send("\033/Z", 3, 0);
                    break;
                  case '=':
                    app_keypad_keys = TRUE;
                    break;
                  case '>':
                    app_keypad_keys = FALSE;
                    break;
                  case '<':
                    /* XXX This should switch to VT100 mode not current or default
                     *     VT mode. But this will only have effect in a VT220+
                     *     emulation.
                     */
                    vt52_mode = FALSE;
                    blink_is_real = cfg.blinktext;
                    break;
#if 0
                  case '^':
                    /* XXX Enter auto print mode */
                    break;
                  case '_':
                    /* XXX Exit auto print mode */
                    break;
                  case ']':
                    /* XXX Print screen */
                    break;
#endif

#ifdef VT52_PLUS
                  case 'E':
                    /* compatibility(ATARI) */
                    move(0, 0, 0);
                    erase_lots(FALSE, FALSE, TRUE);
                    disptop = 0;
                    break;
                  case 'L':
                    /* compatibility(ATARI) */
                    if (curs.y <= marg_b)
                        scroll(curs.y, marg_b, -1, FALSE);
                    break;
                  case 'M':
                    /* compatibility(ATARI) */
                    if (curs.y <= marg_b)
                        scroll(curs.y, marg_b, 1, TRUE);
                    break;
                  case 'b':
                    /* compatibility(ATARI) */
                    termstate = VT52_FG;
                    break;
                  case 'c':
                    /* compatibility(ATARI) */
                    termstate = VT52_BG;
                    break;
                  case 'd':
                    /* compatibility(ATARI) */
                    erase_lots(FALSE, TRUE, FALSE);
                    disptop = 0;
                    break;
                  case 'e':
                    /* compatibility(ATARI) */
                    cursor_on = TRUE;
                    break;
                  case 'f':
                    /* compatibility(ATARI) */
                    cursor_on = FALSE;
                    break;
                    /* case 'j': Save cursor position - broken on ST */
                    /* case 'k': Restore cursor position */
                  case 'l':
                    /* compatibility(ATARI) */
                    erase_lots(TRUE, TRUE, TRUE);
                    curs.x = 0;
                    wrapnext = FALSE;
                    fix_cpos;
                    break;
                  case 'o':
                    /* compatibility(ATARI) */
                    erase_lots(TRUE, TRUE, FALSE);
                    break;
                  case 'p':
                    /* compatibility(ATARI) */
                    curr_attr |= ATTR_REVERSE;
                    break;
                  case 'q':
                    /* compatibility(ATARI) */
                    curr_attr &= ~ATTR_REVERSE;
                    break;
                  case 'v':            /* wrap Autowrap on - Wyse style */
                    /* compatibility(ATARI) */
                    wrap = 1;
                    break;
                  case 'w':            /* Autowrap off */
                    /* compatibility(ATARI) */
                    wrap = 0;
                    break;

                  case 'R':
                    /* compatibility(OTHER) */
                    vt52_bold = FALSE;
                    curr_attr = ATTR_DEFAULT;
                    if (use_bce)
                        erase_char = (' ' | ATTR_ASCII |
                                     (curr_attr & 
                                      (ATTR_FGMASK | ATTR_BGMASK)));
                    break;
                  case 'S':
                    /* compatibility(VI50) */
                    curr_attr |= ATTR_UNDER;
                    break;
                  case 'W':
                    /* compatibility(VI50) */
                    curr_attr &= ~ATTR_UNDER;
                    break;
                  case 'U':
                    /* compatibility(VI50) */
                    vt52_bold = TRUE;
                    curr_attr |= ATTR_BOLD;
                    break;
                  case 'T':
                    /* compatibility(VI50) */
                    vt52_bold = FALSE;
                    curr_attr &= ~ATTR_BOLD;
                    break;
#endif
                }
                break;
              case VT52_Y1:
                termstate = VT52_Y2;
                move(curs.x, c - ' ', 0);
                break;
              case VT52_Y2:
                termstate = TOPLEVEL;
                move(c - ' ', curs.y, 0);
                break;

#ifdef VT52_PLUS
              case VT52_FG:
                termstate = TOPLEVEL;
                curr_attr &= ~ATTR_FGMASK;
                curr_attr &= ~ATTR_BOLD;
                curr_attr |= (c & 0x7) << ATTR_FGSHIFT;
                if ((c & 0x8) || vt52_bold)
                    curr_attr |= ATTR_BOLD;

                if (use_bce)
                    erase_char = (' ' | ATTR_ASCII |
                                 (curr_attr & (ATTR_FGMASK | ATTR_BGMASK)));
                break;
              case VT52_BG:
                termstate = TOPLEVEL;
                curr_attr &= ~ATTR_BGMASK;
                curr_attr &= ~ATTR_BLINK;
                curr_attr |= (c & 0x7) << ATTR_BGSHIFT;

                /* Note: bold background */
                if (c & 0x8)
                    curr_attr |= ATTR_BLINK;

                if (use_bce)
                    erase_char = (' ' | ATTR_ASCII |
                                 (curr_attr & (ATTR_FGMASK | ATTR_BGMASK)));
                break;
#endif
              default: break;          /* placate gcc warning about enum use */
            }
        if (selstate != NO_SELECTION) {
            pos cursplus = curs;
            incpos(cursplus);
            check_selection(curs, cursplus);
        }
    }

    term_print_flush();
}

#if 0
/*
 * Compare two lines to determine whether they are sufficiently
 * alike to scroll-optimise one to the other. Return the degree of
 * similarity.
 */
static int linecmp(unsigned long *a, unsigned long *b)
{
    int i, n;

    for (i = n = 0; i < cols; i++)
        n += (*a++ == *b++);
    return n;
}
#endif

/*
 * Given a context, update the window. Out of paranoia, we don't
 * allow WM_PAINT responses to do scrolling optimisations.
 */
static void do_paint(Context ctx, int may_optimise)
{
    int i, j, our_curs_y;
    unsigned long rv, cursor;
    pos scrpos;
    char ch[1024];
    long cursor_background = ERASE_CHAR;
    unsigned long ticks;

    /*
     * Check the visual bell state.
     */
    if (in_vbell) {
        ticks = GETTICKCOUNT();
        if (ticks - vbell_startpoint >= VBELL_TIMEOUT)
            in_vbell = FALSE; 
   }

    rv = (!rvideo ^ !in_vbell ? ATTR_REVERSE : 0);

    /* Depends on:
     * screen array, disptop, scrtop,
     * selection, rv, 
     * cfg.blinkpc, blink_is_real, tblinker, 
     * curs.y, curs.x, blinker, cfg.blink_cur, cursor_on, has_focus, wrapnext
     */

    /* Has the cursor position or type changed ? */
    if (cursor_on) {
        if (has_focus) {
            if (blinker || !cfg.blink_cur)
                cursor = TATTR_ACTCURS;
            else
                cursor = 0;
        } else
            cursor = TATTR_PASCURS;
        if (wrapnext)
            cursor |= TATTR_RIGHTCURS;
    } else
        cursor = 0;
    our_curs_y = curs.y - disptop;

    if (dispcurs && (curstype != cursor ||
                     dispcurs !=
                     disptext + our_curs_y * (cols + 1) + curs.x)) {
        if (dispcurs > disptext && 
                (*dispcurs & (CHAR_MASK | CSET_MASK)) == UCSWIDE)
            dispcurs[-1] |= ATTR_INVALID;
        if ( (dispcurs[1] & (CHAR_MASK | CSET_MASK)) == UCSWIDE)
            dispcurs[1] |= ATTR_INVALID;
        *dispcurs |= ATTR_INVALID;
        curstype = 0;
    }
    dispcurs = NULL;

    /* The normal screen data */
    for (i = 0; i < rows; i++) {
        unsigned long *ldata;
        int lattr;
        int idx, dirty_line, dirty_run, selected;
        unsigned long attr = 0;
        int updated_line = 0;
        int start = 0;
        int ccount = 0;
        int last_run_dirty = 0;

        scrpos.y = i + disptop;
        ldata = lineptr(scrpos.y);
        lattr = (ldata[cols] & LATTR_MODE);

        idx = i * (cols + 1);
        dirty_run = dirty_line = (ldata[cols] != disptext[idx + cols]);
        disptext[idx + cols] = ldata[cols];

        for (j = 0; j < cols; j++, idx++) {
            unsigned long tattr, tchar;
            unsigned long *d = ldata + j;
            int break_run;
            scrpos.x = j;

            tchar = (*d & (CHAR_MASK | CSET_MASK));
            tattr = (*d & (ATTR_MASK ^ CSET_MASK));
            switch (tchar & CSET_MASK) {
              case ATTR_ASCII:
                tchar = unitab_line[tchar & 0xFF];
                break;
              case ATTR_LINEDRW:
                tchar = unitab_xterm[tchar & 0xFF];
                break;
              case ATTR_SCOACS:  
                tchar = unitab_scoacs[tchar&0xFF]; 
                break;
            }
            tattr |= (tchar & CSET_MASK);
            tchar &= CHAR_MASK;
            if ((d[1] & (CHAR_MASK | CSET_MASK)) == UCSWIDE)
                    tattr |= ATTR_WIDE;

            /* Video reversing things */
            if (seltype == LEXICOGRAPHIC)
                selected = posle(selstart, scrpos) && poslt(scrpos, selend);
            else
                selected = posPle(selstart, scrpos) && posPlt(scrpos, selend);
            tattr = (tattr ^ rv
                     ^ (selected ? ATTR_REVERSE : 0));

            /* 'Real' blinking ? */
            if (blink_is_real && (tattr & ATTR_BLINK)) {
                if (has_focus && tblinker) {
                    tchar = ' ';
                    tattr &= ~CSET_MASK;
                    tattr |= ATTR_ACP;
                }
                tattr &= ~ATTR_BLINK;
            }

            /*
             * Check the font we'll _probably_ be using to see if 
             * the character is wide when we don't want it to be.
             */
            if ((tchar | tattr) != (disptext[idx]& ~ATTR_NARROW)) {
                if ((tattr & ATTR_WIDE) == 0 && 
                    CharWidth(ctx, (tchar | tattr) & 0xFFFF) == 2)
                    tattr |= ATTR_NARROW;
            } else if (disptext[idx]&ATTR_NARROW)
                tattr |= ATTR_NARROW;

            /* Cursor here ? Save the 'background' */
            if (i == our_curs_y && j == curs.x) {
                cursor_background = tattr | tchar;
                dispcurs = disptext + idx;
            }

            if ((disptext[idx] ^ tattr) & ATTR_WIDE)
                dirty_line = TRUE;

            break_run = (tattr != attr || j - start >= sizeof(ch));

            /* Special hack for VT100 Linedraw glyphs */
            if ((attr & CSET_MASK) == 0x2300 && tchar >= 0xBA
                && tchar <= 0xBD) break_run = TRUE;

            if (!dbcs_screenfont && !dirty_line) {
                if ((tchar | tattr) == disptext[idx])
                    break_run = TRUE;
                else if (!dirty_run && ccount == 1)
                    break_run = TRUE;
            }

            if (break_run) {
                if ((dirty_run || last_run_dirty) && ccount > 0) {
                    do_text(ctx, start, i, ch, ccount, attr, lattr);
                    updated_line = 1;
                }
                start = j;
                ccount = 0;
                attr = tattr;
                if (dbcs_screenfont)
                    last_run_dirty = dirty_run;
                dirty_run = dirty_line;
            }

            if ((tchar | tattr) != disptext[idx])
                dirty_run = TRUE;
            ch[ccount++] = (char) tchar;
            disptext[idx] = tchar | tattr;

            /* If it's a wide char step along to the next one. */
            if (tattr & ATTR_WIDE) {
                if (++j < cols) {
                    idx++;
                    d++;
                    /* Cursor is here ? Ouch! */
                    if (i == our_curs_y && j == curs.x) {
                        cursor_background = *d;
                        dispcurs = disptext + idx;
                    }
                    if (disptext[idx] != *d)
                        dirty_run = TRUE;
                    disptext[idx] = *d;
                }
            }
        }
        if (dirty_run && ccount > 0) {
            do_text(ctx, start, i, ch, ccount, attr, lattr);
            updated_line = 1;
        }

        /* Cursor on this line ? (and changed) */
        if (i == our_curs_y && (curstype != cursor || updated_line)) {
            ch[0] = (char) (cursor_background & CHAR_MASK);
            attr = (cursor_background & ATTR_MASK) | cursor;
            do_cursor(ctx, curs.x, i, ch, 1, attr, lattr);
            curstype = cursor;
        }
    }
}

/*
 * Flick the switch that says if blinking things should be shown or hidden.
 */

void term_blink(int flg)
{
    static long last_blink = 0;
    static long last_tblink = 0;
    long now, blink_diff;

    now = GETTICKCOUNT();
    blink_diff = now - last_tblink;

    /* Make sure the text blinks no more than 2Hz; we'll use 0.45 s period. */
    if (blink_diff < 0 || blink_diff > (TICKSPERSEC * 9 / 20)) {
        last_tblink = now;
        tblinker = !tblinker;
    }

    if (flg) {
        blinker = 1;
        last_blink = now;
        return;
    }

    blink_diff = now - last_blink;

    /* Make sure the cursor blinks no faster than system blink rate */
    if (blink_diff >= 0 && blink_diff < (long) CURSORBLINK)
        return;

    last_blink = now;
    blinker = !blinker;
}

/*
 * Invalidate the whole screen so it will be repainted in full.
 */
void term_invalidate(void)
{
    int i;

    for (i = 0; i < rows * (cols + 1); i++)
        disptext[i] = ATTR_INVALID;
}

/*
 * Paint the window in response to a WM_PAINT message.
 */
void term_paint(Context ctx, int left, int top, int right, int bottom)
{
    int i, j;
    if (left < 0) left = 0;
    if (top < 0) top = 0;
    if (right >= cols) right = cols-1;
    if (bottom >= rows) bottom = rows-1;

    for (i = top; i <= bottom && i < rows; i++) {
        if ((disptext[i * (cols + 1) + cols] & LATTR_MODE) == LATTR_NORM)
            for (j = left; j <= right && j < cols; j++)
                disptext[i * (cols + 1) + j] = ATTR_INVALID;
        else
            for (j = left / 2; j <= right / 2 + 1 && j < cols; j++)
                disptext[i * (cols + 1) + j] = ATTR_INVALID;
    }

    /* This should happen soon enough, also for some reason it sometimes 
     * fails to actually do anything when re-sizing ... painting the wrong
     * window perhaps ?
     */
    if (alt_pressed)
        do_paint (ctx, FALSE);
}

/*
 * Attempt to scroll the scrollback. The second parameter gives the
 * position we want to scroll to; the first is +1 to denote that
 * this position is relative to the beginning of the scrollback, -1
 * to denote it is relative to the end, and 0 to denote that it is
 * relative to the current position.
 */
void term_scroll(int rel, int where)
{
    int sbtop = -count234(scrollback);

    disptop = (rel < 0 ? 0 : rel > 0 ? sbtop : disptop) + where;
    if (disptop < sbtop)
        disptop = sbtop;
    if (disptop > 0)
        disptop = 0;
    update_sbar();
    term_update();
}

static void clipme(pos top, pos bottom, int rect)
{
    wchar_t *workbuf;
    wchar_t *wbptr;                    /* where next char goes within workbuf */
    int old_top_x;
    int wblen = 0;                     /* workbuf len */
    int buflen;                        /* amount of memory allocated to workbuf */

    buflen = 5120;                     /* Default size */
    workbuf = smalloc(buflen * sizeof(wchar_t));
    wbptr = workbuf;                   /* start filling here */
    old_top_x = top.x;                 /* needed for rect==1 */

    while (poslt(top, bottom)) {
        int nl = FALSE;
        unsigned long *ldata = lineptr(top.y);
        pos nlpos;

        /*
         * nlpos will point at the maximum position on this line we
         * should copy up to. So we start it at the end of the
         * line...
         */
        nlpos.y = top.y;
        nlpos.x = cols;

        /*
         * ... move it backwards if there's unused space at the end
         * of the line (and also set `nl' if this is the case,
         * because in normal selection mode this means we need a
         * newline at the end)...
         */
        if (!(ldata[cols] & LATTR_WRAPPED)) {
            while (((ldata[nlpos.x - 1] & 0xFF) == 0x20 ||
                    (DIRECT_CHAR(ldata[nlpos.x - 1]) &&
                     (ldata[nlpos.x - 1] & CHAR_MASK) == 0x20))
                   && poslt(top, nlpos))
                decpos(nlpos);
            if (poslt(nlpos, bottom))
                nl = TRUE;
        }

        /*
         * ... and then clip it to the terminal x coordinate if
         * we're doing rectangular selection. (In this case we
         * still did the above, so that copying e.g. the right-hand
         * column from a table doesn't fill with spaces on the
         * right.)
         */
        if (rect) {
            if (nlpos.x > bottom.x)
                nlpos.x = bottom.x;
            nl = (top.y < bottom.y);
        }

        while (poslt(top, bottom) && poslt(top, nlpos)) {
#if 0
            char cbuf[16], *p;
            sprintf(cbuf, "<U+%04x>", (ldata[top.x] & 0xFFFF));
#else
            wchar_t cbuf[16], *p;
            int uc = (ldata[top.x] & 0xFFFF);
            int set, c;

            if (uc == UCSWIDE) {
                top.x++;
                continue;
            }

            switch (uc & CSET_MASK) {
              case ATTR_LINEDRW:
                if (!cfg.rawcnp) {
                    uc = unitab_xterm[uc & 0xFF];
                    break;
                }
              case ATTR_ASCII:
                uc = unitab_line[uc & 0xFF];
                break;
              case ATTR_SCOACS:  
                uc = unitab_scoacs[uc&0xFF]; 
                break;
            }
            switch (uc & CSET_MASK) {
              case ATTR_ACP:
                uc = unitab_font[uc & 0xFF];
                break;
              case ATTR_OEMCP:
                uc = unitab_oemcp[uc & 0xFF];
                break;
            }

            set = (uc & CSET_MASK);
            c = (uc & CHAR_MASK);
            cbuf[0] = uc;
            cbuf[1] = 0;

            if (DIRECT_FONT(uc)) {
                if (c >= ' ' && c != 0x7F) {
                    unsigned char buf[4];
                    WCHAR wbuf[4];
                    int rv;
                    if (is_dbcs_leadbyte(font_codepage, (BYTE) c)) {
                        buf[0] = c;
                        buf[1] = (unsigned char) ldata[top.x + 1];
                        rv = mb_to_wc(font_codepage, 0, buf, 2, wbuf, 4);
                        top.x++;
                    } else {
                        buf[0] = c;
                        rv = mb_to_wc(font_codepage, 0, buf, 1, wbuf, 4);
                    }

                    if (rv > 0) {
                        memcpy(cbuf, wbuf, rv * sizeof(wchar_t));
                        cbuf[rv] = 0;
                    }
                }
            }
#endif

            for (p = cbuf; *p; p++) {
                /* Enough overhead for trailing NL and nul */
                if (wblen >= buflen - 16) {
                    workbuf =
                        srealloc(workbuf,
                                 sizeof(wchar_t) * (buflen += 100));
                    wbptr = workbuf + wblen;
                }
                wblen++;
                *wbptr++ = *p;
            }
            top.x++;
        }
        if (nl) {
            int i;
            for (i = 0; i < sel_nl_sz; i++) {
                wblen++;
                *wbptr++ = sel_nl[i];
            }
        }
        top.y++;
        top.x = rect ? old_top_x : 0;
    }
#if SELECTION_NUL_TERMINATED
    wblen++;
    *wbptr++ = 0;
#endif
    write_clip(workbuf, wblen, FALSE); /* transfer to clipboard */
    if (buflen > 0)                    /* indicates we allocated this buffer */
        sfree(workbuf);
}

void term_copyall(void)
{
    pos top;
    top.y = -count234(scrollback);
    top.x = 0;
    clipme(top, curs, 0);
}

/*
 * The wordness array is mainly for deciding the disposition of the US-ASCII 
 * characters.
 */
static int wordtype(int uc)
{
    static struct {
        int start, end, ctype;
    } *wptr, ucs_words[] = {
        {
        128, 160, 0}, {
        161, 191, 1}, {
        215, 215, 1}, {
        247, 247, 1}, {
        0x037e, 0x037e, 1},            /* Greek question mark */
        {
        0x0387, 0x0387, 1},            /* Greek ano teleia */
        {
        0x055a, 0x055f, 1},            /* Armenian punctuation */
        {
        0x0589, 0x0589, 1},            /* Armenian full stop */
        {
        0x0700, 0x070d, 1},            /* Syriac punctuation */
        {
        0x104a, 0x104f, 1},            /* Myanmar punctuation */
        {
        0x10fb, 0x10fb, 1},            /* Georgian punctuation */
        {
        0x1361, 0x1368, 1},            /* Ethiopic punctuation */
        {
        0x166d, 0x166e, 1},            /* Canadian Syl. punctuation */
        {
        0x17d4, 0x17dc, 1},            /* Khmer punctuation */
        {
        0x1800, 0x180a, 1},            /* Mongolian punctuation */
        {
        0x2000, 0x200a, 0},            /* Various spaces */
        {
        0x2070, 0x207f, 2},            /* superscript */
        {
        0x2080, 0x208f, 2},            /* subscript */
        {
        0x200b, 0x27ff, 1},            /* punctuation and symbols */
        {
        0x3000, 0x3000, 0},            /* ideographic space */
        {
        0x3001, 0x3020, 1},            /* ideographic punctuation */
        {
        0x303f, 0x309f, 3},            /* Hiragana */
        {
        0x30a0, 0x30ff, 3},            /* Katakana */
        {
        0x3300, 0x9fff, 3},            /* CJK Ideographs */
        {
        0xac00, 0xd7a3, 3},            /* Hangul Syllables */
        {
        0xf900, 0xfaff, 3},            /* CJK Ideographs */
        {
        0xfe30, 0xfe6b, 1},            /* punctuation forms */
        {
        0xff00, 0xff0f, 1},            /* half/fullwidth ASCII */
        {
        0xff1a, 0xff20, 1},            /* half/fullwidth ASCII */
        {
        0xff3b, 0xff40, 1},            /* half/fullwidth ASCII */
        {
        0xff5b, 0xff64, 1},            /* half/fullwidth ASCII */
        {
        0xfff0, 0xffff, 0},            /* half/fullwidth ASCII */
        {
        0, 0, 0}
    };

    uc &= (CSET_MASK | CHAR_MASK);

    switch (uc & CSET_MASK) {
      case ATTR_LINEDRW:
        uc = unitab_xterm[uc & 0xFF];
        break;
      case ATTR_ASCII:
        uc = unitab_line[uc & 0xFF];
        break;
      case ATTR_SCOACS:  
        uc = unitab_scoacs[uc&0xFF]; 
        break;
    }
    switch (uc & CSET_MASK) {
      case ATTR_ACP:
        uc = unitab_font[uc & 0xFF];
        break;
      case ATTR_OEMCP:
        uc = unitab_oemcp[uc & 0xFF];
        break;
    }

    /* For DBCS font's I can't do anything usefull. Even this will sometimes
     * fail as there's such a thing as a double width space. :-(
     */
    if (dbcs_screenfont && font_codepage == line_codepage)
        return (uc != ' ');

    if (uc < 0x80)
        return wordness[uc];

    for (wptr = ucs_words; wptr->start; wptr++) {
        if (uc >= wptr->start && uc <= wptr->end)
            return wptr->ctype;
    }

    return 2;
}

/*
 * Spread the selection outwards according to the selection mode.
 */
static pos sel_spread_half(pos p, int dir)
{
    unsigned long *ldata;
    short wvalue;
    int topy = -count234(scrollback);

    ldata = lineptr(p.y);

    switch (selmode) {
      case SM_CHAR:
        /*
         * In this mode, every character is a separate unit, except
         * for runs of spaces at the end of a non-wrapping line.
         */
        if (!(ldata[cols] & LATTR_WRAPPED)) {
            unsigned long *q = ldata + cols;
            while (q > ldata && (q[-1] & CHAR_MASK) == 0x20)
                q--;
            if (q == ldata + cols)
                q--;
            if (p.x >= q - ldata)
                p.x = (dir == -1 ? q - ldata : cols - 1);
        }
        break;
      case SM_WORD:
        /*
         * In this mode, the units are maximal runs of characters
         * whose `wordness' has the same value.
         */
        wvalue = wordtype(ldata[p.x]);
        if (dir == +1) {
            while (1) {
                if (p.x < cols-1) {
                    if (wordtype(ldata[p.x + 1]) == wvalue)
                        p.x++;
                    else
                        break;
                } else {
                    if (ldata[cols] & LATTR_WRAPPED) {
                        unsigned long *ldata2;
                        ldata2 = lineptr(p.y+1);
                        if (wordtype(ldata2[0]) == wvalue) {
                            p.x = 0;
                            p.y++;
                            ldata = ldata2;
                        } else
                            break;
                    } else
                        break;
                }
            }
        } else {
            while (1) {
                if (p.x > 0) {
                    if (wordtype(ldata[p.x - 1]) == wvalue)
                        p.x--;
                    else
                        break;
                } else {
                    unsigned long *ldata2;
                    if (p.y <= topy)
                        break;
                    ldata2 = lineptr(p.y-1);
                    if ((ldata2[cols] & LATTR_WRAPPED) &&
                        wordtype(ldata2[cols-1]) == wvalue) {
                        p.x = cols-1;
                        p.y--;
                        ldata = ldata2;
                    } else
                        break;
                }
            }
        }
        break;
      case SM_LINE:
        /*
         * In this mode, every line is a unit.
         */
        p.x = (dir == -1 ? 0 : cols - 1);
        break;
    }
    return p;
}

static void sel_spread(void)
{
    if (seltype == LEXICOGRAPHIC) {
        selstart = sel_spread_half(selstart, -1);
        decpos(selend);
        selend = sel_spread_half(selend, +1);
        incpos(selend);
    }
}

void term_do_paste(void)
{
    wchar_t *data;
    int len;

    get_clip(&data, &len);
    if (data && len > 0) {
        wchar_t *p, *q;

        term_seen_key_event();         /* pasted data counts */

        if (paste_buffer)
            sfree(paste_buffer);
        paste_pos = paste_hold = paste_len = 0;
        paste_buffer = smalloc(len * sizeof(wchar_t));

        p = q = data;
        while (p < data + len) {
            while (p < data + len &&
                   !(p <= data + len - sel_nl_sz &&
                     !memcmp(p, sel_nl, sizeof(sel_nl))))
                p++;

            {
                int i;
                for (i = 0; i < p - q; i++) {
                    paste_buffer[paste_len++] = q[i];
                }
            }

            if (p <= data + len - sel_nl_sz &&
                !memcmp(p, sel_nl, sizeof(sel_nl))) {
                paste_buffer[paste_len++] = '\r';
                p += sel_nl_sz;
            }
            q = p;
        }

        /* Assume a small paste will be OK in one go. */
        if (paste_len < 256) {
            luni_send(paste_buffer, paste_len, 0);
            if (paste_buffer)
                sfree(paste_buffer);
            paste_buffer = 0;
            paste_pos = paste_hold = paste_len = 0;
        }
    }
    get_clip(NULL, NULL);
}

void term_mouse(Mouse_Button b, Mouse_Action a, int x, int y,
                int shift, int ctrl, int alt)
{
    pos selpoint;
    unsigned long *ldata;
    int raw_mouse = (xterm_mouse &&
                     !cfg.no_mouse_rep &&
                     !(cfg.mouse_override && shift));
    int default_seltype;

    if (y < 0) {
        y = 0;
        if (a == MA_DRAG && !raw_mouse)
            term_scroll(0, -1);
    }
    if (y >= rows) {
        y = rows - 1;
        if (a == MA_DRAG && !raw_mouse)
            term_scroll(0, +1);
    }
    if (x < 0) {
        if (y > 0) {
            x = cols - 1;
            y--;
        } else
            x = 0;
    }
    if (x >= cols)
        x = cols - 1;

    selpoint.y = y + disptop;
    selpoint.x = x;
    ldata = lineptr(selpoint.y);
    if ((ldata[cols] & LATTR_MODE) != LATTR_NORM)
        selpoint.x /= 2;

    if (raw_mouse) {
        int encstate = 0, r, c;
        char abuf[16];
        static int is_down = 0;

        switch (b) {
          case MBT_LEFT:
            encstate = 0x20;           /* left button down */
            break;
          case MBT_MIDDLE:
            encstate = 0x21;
            break;
          case MBT_RIGHT:
            encstate = 0x22;
            break;
          case MBT_WHEEL_UP:
            encstate = 0x60;
            break;
          case MBT_WHEEL_DOWN:
            encstate = 0x61;
            break;
          default: break;              /* placate gcc warning about enum use */
        }
        switch (a) {
          case MA_DRAG:
            if (xterm_mouse == 1)
                return;
            encstate += 0x20;
            break;
          case MA_RELEASE:
            encstate = 0x23;
            is_down = 0;
            break;
          case MA_CLICK:
            if (is_down == b)
                return;
            is_down = b;
            break;
          default: break;              /* placate gcc warning about enum use */
        }
        if (shift)
            encstate += 0x04;
        if (ctrl)
            encstate += 0x10;
        r = y + 33;
        c = x + 33;

        sprintf(abuf, "\033[M%c%c%c", encstate, c, r);
        ldisc_send(abuf, 6, 0);
        return;
    }

    b = translate_button(b);

    /*
     * Set the selection type (rectangular or normal) at the start
     * of a selection attempt, from the state of Alt.
     */
    if (!alt ^ !cfg.rect_select)
        default_seltype = RECTANGULAR;
    else
        default_seltype = LEXICOGRAPHIC;
        
    if (selstate == NO_SELECTION) {
        seltype = default_seltype;
    }

    if (b == MBT_SELECT && a == MA_CLICK) {
        deselect();
        selstate = ABOUT_TO;
        seltype = default_seltype;
        selanchor = selpoint;
        selmode = SM_CHAR;
    } else if (b == MBT_SELECT && (a == MA_2CLK || a == MA_3CLK)) {
        deselect();
        selmode = (a == MA_2CLK ? SM_WORD : SM_LINE);
        selstate = DRAGGING;
        selstart = selanchor = selpoint;
        selend = selstart;
        incpos(selend);
        sel_spread();
    } else if ((b == MBT_SELECT && a == MA_DRAG) ||
               (b == MBT_EXTEND && a != MA_RELEASE)) {
        if (selstate == ABOUT_TO && poseq(selanchor, selpoint))
            return;
        if (b == MBT_EXTEND && a != MA_DRAG && selstate == SELECTED) {
            if (seltype == LEXICOGRAPHIC) {
                /*
                 * For normal selection, we extend by moving
                 * whichever end of the current selection is closer
                 * to the mouse.
                 */
                if (posdiff(selpoint, selstart) <
                    posdiff(selend, selstart) / 2) {
                    selanchor = selend;
                    decpos(selanchor);
                } else {
                    selanchor = selstart;
                }
            } else {
                /*
                 * For rectangular selection, we have a choice of
                 * _four_ places to put selanchor and selpoint: the
                 * four corners of the selection.
                 */
                if (2*selpoint.x < selstart.x + selend.x)
                    selanchor.x = selend.x-1;
                else
                    selanchor.x = selstart.x;

                if (2*selpoint.y < selstart.y + selend.y)
                    selanchor.y = selend.y;
                else
                    selanchor.y = selstart.y;
            }
            selstate = DRAGGING;
        }
        if (selstate != ABOUT_TO && selstate != DRAGGING)
            selanchor = selpoint;
        selstate = DRAGGING;
        if (seltype == LEXICOGRAPHIC) {
            /*
             * For normal selection, we set (selstart,selend) to
             * (selpoint,selanchor) in some order.
             */
            if (poslt(selpoint, selanchor)) {
                selstart = selpoint;
                selend = selanchor;
                incpos(selend);
            } else {
                selstart = selanchor;
                selend = selpoint;
                incpos(selend);
            }
        } else {
            /*
             * For rectangular selection, we may need to
             * interchange x and y coordinates (if the user has
             * dragged in the -x and +y directions, or vice versa).
             */
            selstart.x = min(selanchor.x, selpoint.x);
            selend.x = 1+max(selanchor.x, selpoint.x);
            selstart.y = min(selanchor.y, selpoint.y);
            selend.y =   max(selanchor.y, selpoint.y);
        }
        sel_spread();
    } else if ((b == MBT_SELECT || b == MBT_EXTEND) && a == MA_RELEASE) {
        if (selstate == DRAGGING) {
            /*
             * We've completed a selection. We now transfer the
             * data to the clipboard.
             */
            clipme(selstart, selend, (seltype == RECTANGULAR));
            selstate = SELECTED;
        } else
            selstate = NO_SELECTION;
    } else if (b == MBT_PASTE
               && (a == MA_CLICK
#if MULTICLICK_ONLY_EVENT
                   || a == MA_2CLK || a == MA_3CLK
#endif
                   )) {
        request_paste();
    }

    term_update();
}

void term_nopaste()
{
    if (paste_len == 0)
        return;
    sfree(paste_buffer);
    paste_buffer = 0;
    paste_len = 0;
}

int term_paste_pending(void)
{
    return paste_len != 0;
}

void term_paste()
{
    static long last_paste = 0;
    long now, paste_diff;

    if (paste_len == 0)
        return;

    /* Don't wait forever to paste */
    if (paste_hold) {
        now = GETTICKCOUNT();
        paste_diff = now - last_paste;
        if (paste_diff >= 0 && paste_diff < 450)
            return;
    }
    paste_hold = 0;

    while (paste_pos < paste_len) {
        int n = 0;
        while (n + paste_pos < paste_len) {
            if (paste_buffer[paste_pos + n++] == '\r')
                break;
        }
        luni_send(paste_buffer + paste_pos, n, 0);
        paste_pos += n;

        if (paste_pos < paste_len) {
            paste_hold = 1;
            return;
        }
    }
    sfree(paste_buffer);
    paste_buffer = 0;
    paste_len = 0;
}

static void deselect(void)
{
    selstate = NO_SELECTION;
    selstart.x = selstart.y = selend.x = selend.y = 0;
}

void term_deselect(void)
{
    deselect();
    term_update();
}

int term_ldisc(int option)
{
    if (option == LD_ECHO)
        return term_echoing;
    if (option == LD_EDIT)
        return term_editing;
    return FALSE;
}

/*
 * from_backend(), to get data from the backend for the terminal.
 */
int from_backend(int is_stderr, char *data, int len)
{
    assert(len > 0);

    bufchain_add(&inbuf, data, len);

    /*
     * term_out() always completely empties inbuf. Therefore,
     * there's no reason at all to return anything other than zero
     * from this function, because there _can't_ be a question of
     * the remote side needing to wait until term_out() has cleared
     * a backlog.
     *
     * This is a slightly suboptimal way to deal with SSH2 - in
     * principle, the window mechanism would allow us to continue
     * to accept data on forwarded ports and X connections even
     * while the terminal processing was going slowly - but we
     * can't do the 100% right thing without moving the terminal
     * processing into a separate thread, and that might hurt
     * portability. So we manage stdout buffering the old SSH1 way:
     * if the terminal processing goes slowly, the whole SSH
     * connection stops accepting data until it's ready.
     *
     * In practice, I can't imagine this causing serious trouble.
     */
    return 0;
}